Communication of an interference condition in wireless communications systems

ABSTRACT

Systems, devices, and methods for adjusting a transmission power at a femto node are described herein. According to the systems, devices, and methods herein, a measurement of a signal transmitted from a transmitting node may be communicated to the femto node, for example from a user equipment or a neighboring femto node, for use in adjusting the power. The transmitting node may comprise the femto node, a macro node, or a neighboring femto node. In addition, statistics regarding such measurements may be communicated to the femto node for use in adjusting the power. The femto node may also adjust the power based on unsuccessful registration attempts or interference communications received at the femto node.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present Application for Patent claims priority to U.S. ProvisionalApplication No. 61/172,033, entitled “Home User Equipment Assisted HomeNodeB Power Calibration,” filed Apr. 23, 2009; U.S. ProvisionalApplication No. 61/172,038, entitled “Macro User Equipment Assisted HomeNodeB Power Calibration,” filed Apr. 23, 2009; U.S. ProvisionalApplication No. 61/174,611, entitled “MUE REGISTRATION BASED HNB POWERCALIBRATION,” filed May 1, 2009; and U.S. Provisional Application No.61/304,284, entitled “Macro User Equipment Assisted Home NodeB PowerCalibration,” filed Feb. 12, 2010. The above-referenced applications arehereby expressly incorporated by reference herein in their entireties.

REFERENCE TO CO-PENDING APPLICATIONS FOR PATENT

The present Application for Patent is related to the followingco-pending U.S. Patent Applications:

“Femto Node Power Adjustment Using Requests for Registration,” havingSer. No. 12/765,375, filed concurrently herewith, assigned to theassignee hereof, and expressly incorporated by reference herein.

“Femto Node Power Adjustment in Wireless Communications Systems,” havingSer. No. 12/765,382, filed concurrently herewith, assigned to theassignee hereof, and expressly incorporated by reference herein.

“Measurement Aggregation in Wireless Communications Systems,” havingSer. No. 12/765,382, filed concurrently herewith, assigned to theassignee hereof, and expressly incorporated by reference herein.

BACKGROUND

1. Field

The present application relates generally to wireless communication, andmore specifically to systems and methods for adjusting a transmit powerat a femto node.

2. Background

Wireless communication systems are widely deployed to provide varioustypes of communication (e.g., voice, data, multimedia services, etc.) tomultiple users. As the demand for high-rate and multimedia data servicesrapidly grows, there lies a challenge to implement efficient and robustcommunication systems with enhanced performance.

In addition to mobile phone networks currently in place, a new class ofsmall base stations has emerged, which may be installed in a user's homeand provide indoor wireless coverage to mobile units using existingbroadband Internet connections. Such personal miniature base stationsare generally known as access point base stations, or, alternatively,Home Node B (HNB) or femto nodes. Typically, such miniature basestations are connected to the Internet and the mobile operator's networkvia a DSL router or a cable modem.

Multiple femto nodes may be deployed by individual users in the coveragearea of a traditional macro node (Macro Node B, or MNB). Users receivingcommunications from a femto node may detect signals from the macro nodein some situations, and users receiving communications from the macronode may in some situations detect signals from the femto node. In orderto accurately receive such communications, it is advantageous to reducethe interference experienced by these users. Thus, methods, systems, anddevices for reducing interference caused by a femto node are desirable.

SUMMARY

The systems, methods, and devices of the invention each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this invention as expressed bythe claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this invention provide advantages that include communicatingan interference condition to a femto node.

One aspect of the disclosure is an apparatus for wireless communication.The apparatus comprises a receiver configured to wirelessly receive asignal transmitted from a transmitting device. In some embodiments, thetransmitting device is associated with at least one user device. In someembodiments, only user devices that are associated with the transmittingdevice are permitted to communicate with other user devices via thetransmitting device. The apparatus further comprises an interferenceunit configured to identify an interference condition based at least inpart on the received signal. The apparatus further comprises adetermination unit configured to determine whether the apparatus isassociated with the transmitting device. The apparatus further comprisesa transmitter configured to wirelessly transmit an interferencecommunication to the transmitting device in response to identifying theinterference condition if the apparatus is not associated with thetransmitting device.

Another aspect of the disclosure is a method of wireless communication.The method comprises wirelessly receiving at an apparatus a signaltransmitted from a transmitting device. In some embodiments, thetransmitting device is associated with at least one user device. In someembodiments, only user devices that are associated with the transmittingdevice are permitted to communicate with other user devices via thetransmitting device. The method further comprises identifying aninterference condition based at least in part on the received signal.The method further comprises determining whether the apparatus isassociated with the transmitting device. The method further compriseswirelessly transmitting an interference communication to thetransmitting device in response to identifying the interferencecondition if the apparatus is not associated with the transmittingdevice.

Yet another aspect of the disclosure is an apparatus for wirelesscommunication. The apparatus comprises means for wirelessly receiving atan apparatus a signal transmitted from a transmitting device. In someembodiments, the transmitting device is associated with at least oneuser device. In some embodiments, only user devices that are associatedwith the transmitting device are permitted to communicate with otheruser devices via the transmitting device. The apparatus furthercomprises means for identifying an interference condition based at leastin part on the received signal. The apparatus further comprises meansfor determining whether the apparatus is associated with thetransmitting device. The apparatus further comprises means forwirelessly transmitting an interference communication to thetransmitting device in response to identifying the interferencecondition if the apparatus is not associated with the transmittingdevice.

Still another aspect of the disclosure is a computer program productcomprising a computer-readable medium. The computer-readable mediumcomprises code for causing a computer to wirelessly receive a signaltransmitted from a transmitting device. In some embodiments, thetransmitting device is associated with at least one user device. In someembodiments, only user devices that are associated with the transmittingdevice are permitted to communicate with other user devices via thetransmitting device. The computer-readable medium further comprises codefor causing a computer to identify an interference condition based atleast in part on the received signal. The computer-readable mediumfurther comprises code for causing a computer to determine whether adevice of the computer which received the signal is associated with thetransmitting device. The computer-readable medium further comprises codefor causing a computer to wirelessly transmitting an interferencecommunication to the transmitting device in response to identifying theinterference condition if the device of the computer is not associatedwith the transmitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary wireless communication network.

FIG. 2 illustrates exemplary interoperations of two or morecommunication networks.

FIG. 3 illustrates exemplary coverage areas of the wirelesscommunication networks shown in FIGS. 1 and 2.

FIG. 4 is a functional block diagram of a first exemplary femto node anda first exemplary user equipment in one of the communication networks ofFIG. 2.

FIG. 5 is a functional block diagram of a second exemplary femto node inone of the communication networks of FIG. 2.

FIG. 6 is a functional block diagram of a second exemplary userequipment in one of the communication networks of FIG. 2.

FIG. 7 is a functional block diagram of an exemplary macro node in oneof the communication networks of FIG. 2.

FIG. 8 is a flow chart illustrating an exemplary process ofcommunication for a user equipment.

FIG. 9 is a flow chart illustrating an exemplary process ofcommunication for a node.

FIG. 10 is a flow chart illustrating an exemplary process of adjusting atransmission power for a femto node.

FIG. 11 is a flow chart illustrating an exemplary process ofcommunication for a user equipment.

FIG. 12 is a flow chart illustrating an exemplary process of adjusting atransmission power for a femto node.

FIG. 13 is a flow chart illustrating an exemplary process of adjusting atransmission power for a femto node.

DETAILED DESCRIPTION

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any embodiment described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other embodiments. The techniques described herein maybe used for various wireless communication networks such as CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA)networks, etc. The terms “networks” and “systems” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000,IS-95 and IS-856 standards. A TDMA network may implement a radiotechnology such as Global System for Mobile Communications (GSM). AnOFDMA network may implement a radio technology such as Evolved UTRA(E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDMA, etc. UTRA,E-UTRA, and GSM are part of Universal Mobile Telecommunication System(UMTS). Long Term Evolution (LTE) is an upcoming release of UMTS thatuses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsfrom an organization named “3rd Generation Partnership Project” (3GPP).cdma2000 is described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). These various radiotechnologies and standards are known in the art.

Single carrier frequency division multiple access (SC-FDMA), whichutilizes single carrier modulation and frequency domain equalization isa technique. SC-FDMA has similar performance and essentially the sameoverall complexity as those of OFDMA system. SC-FDMA signal has lowerpeak-to-average power ratio (PAPR) because of its inherent singlecarrier structure. SC-FDMA has drawn great attention, especially in theuplink communications where lower PAPR greatly benefits the mobileterminal in terms of transmit power efficiency. It is currently aworking assumption for uplink multiple access scheme in 3GPP Long TermEvolution (LTE), or Evolved UTRA.

In some aspects the teachings herein may be employed in a network thatincludes macro scale coverage (e.g., a large area cellular network suchas a 3G networks, typically referred to as a macro cell network) andsmaller scale coverage (e.g., a residence-based or building-basednetwork environment). As a user equipment (“UE”) moves through such anetwork, the user equipment may be served in certain locations by accessnodes (“ANs”) that provide macro coverage while the user equipment maybe served at other locations by access nodes that provide smaller scalecoverage. In some aspects, the smaller coverage nodes may be used toprovide incremental capacity growth, in-building coverage, and differentservices (e.g., for a more robust user experience). In the discussionherein, a node that provides coverage over a relatively large area maybe referred to as a macro node. A node that provides coverage over arelatively small area (e.g., a residence) may be referred to as a femtonode. A node that provides coverage over an area that is smaller than amacro area and larger than a femto area may be referred to as a piconode (e.g., providing coverage within a commercial building).

A cell associated with a macro node, a femto node, or a pico node may bereferred to as a macro cell, a femto cell, or a pico cell, respectively.In some implementations, each cell may be further associated with (e.g.,divided into) one or more sectors.

In various applications, other terminology may be used to reference amacro node, a femto node, or a pico node. For example, a macro node maybe configured or referred to as an access node, base station, accesspoint, eNodeB, macro cell, and so on. Also, a femto node may beconfigured or referred to as a Home NodeB, Home eNodeB, access pointbase station, femto cell, and so on.

FIG. 1 illustrates an exemplary wireless communication network 100. Thewireless communication network 100 is configured to supportcommunication between a number of users. The wireless communicationnetwork 100 may be divided into one or more cells 102, such as, forexample, cells 102A-102G. Communication coverage in cells 102A-102G maybe provided by one or more nodes 104, such as, for example, nodes104A-104G. Each node 104 may provide communication coverage to acorresponding cell 102. The nodes 104 may interact with a plurality ofuser equipments (UEs), such as, for example, UEs 106A-106L.

Each UE 106 may communicate with one or more nodes 104 on a forward link(FL) and/or a reverse link (RL) at a given moment. A FL is acommunication link from a node to a UE. A RL is a communication linkfrom a UE to a node. The nodes 104 may be interconnected, for example,by appropriate wired or wireless interfaces and may be able tocommunicate with each other. Accordingly, each UE 106 may communicatewith another UE 106 through one or more nodes 104. For example, the UE106J may communicate with the UE 106H as follows. The UE 106J maycommunicate with the node 104D. The node 104D may then communicate withthe node 104B. The node 104B may then communicate with the UE 106H.Accordingly, a communication is established between the UE 106J and theUE 106H.

The wireless communication network 100 may provide service over a largegeographic region. For example, the cells 102A-102G may cover only a fewblocks within a neighborhood or several square miles in a ruralenvironment. In one embodiment, each cell may be further divided intoone or more sectors (not shown).

As described above, a node 104 may provide a user equipment (UE) 106access within its coverage area to a communications network, such as,for example the internet or a cellular network.

A UE 106 may be a wireless communication device (e.g., a mobile phone,router, personal computer, server, etc.) used by a user to send andreceive voice or data over a communications network. A user equipment(UE) may also be referred to herein as an access terminal (AT), as amobile station (MS), or as a terminal device. As shown, UEs 106A, 106H,and 106J comprise routers. UEs 106B-106G, 106I, 106K, and 106L comprisemobile phones. However, each of UEs 106A-106L may comprise any suitablecommunication device.

FIG. 2 illustrates exemplary interoperations of two or morecommunication networks. It may be desirable for a UE 220 to transmitinformation to and receive information from another UE such as UE 221.FIG. 2 illustrates a manner in which the UEs 220, 221, and 222 maycommunicate with each other. As shown in FIG. 2, the macro node 205 mayprovide communication coverage to user equipments within a macro area230. For example, the UE 220 may generate and transmit a message to themacro node 205. The message may comprise information related to varioustypes of communication (e.g., voice, data, multimedia services, etc.).The UE 220 may communicate with the macro node 205 via a wireless link.The macro node 205 may communicate with a network 240 via a wired linkor via a wireless link. The femto nodes 210 and 212 may also communicatewith the network 240 via a wired link or via a wireless link. The UE 222may communicate with the femto node 210 via a wireless link and the UE221 may communicate with the femto node 212 via a wireless link.

The macro node 205 may also communicate with devices such as servers(not shown in FIG. 2) and switching centers (not shown in FIG. 2)through the network 240. For example, the macro node 205 may transmitthe message received from the UE 220 to a switching center (not shown inFIG. 2), which may forward the message to another network. The network240 may also be used to facilitate communication between the UEs 220,221, and 222. For example, the UE 220 may be in communication with theUE 221. The UE 220 may transmit a message to the macro node 205. Themacro node 205 may forward the message to the network 240. The network240 may forward the messages to the femto node 212. The femto node 212may forward the message to the UE 221. Similarly, the reverse path maybe followed from the UE 221 to the UE 220. In another example, the UE221 may be in communication with the UE 222. The UE 221 may transmit amessage to the femto node 212. The femto node 212 may forward themessage to the network 240. The network 240 may forward the message tothe femto node 210. The femto node 210 may forward the message to the UE222. Similarly, the reverse path may be followed from the UE 222 to theUE 221.

In one embodiment, the femto nodes 210, 212 may be deployed byindividual consumers and placed in homes, apartment buildings, officebuildings, and the like. The femto nodes 210, 212 may communicate withthe UEs in a predetermined range (e.g., 100 m) of the femto nodes 210,212 utilizing a predetermined cellular transmission band. In oneembodiment, the femto nodes 210, 212 may communicate with the network240 by way of an Internet Protocol (IP) connection, such as a digitalsubscriber line (DSL, e.g., including asymmetric DSL (ADSL), high datarate DSL (HDSL), very high speed DSL (VDSL), etc.), a TV cable carryingInternet Protocol (IP) traffic, a broadband over power line (BPL)connection, or other link.

The network 240 may comprise any type of electronically connected groupof computers and/or devices including, for instance, the followingnetworks: Internet, Intranet, Local Area Networks (LAN) or Wide AreaNetworks (WAN). In addition, the connectivity to the network may be, forexample, remote modem, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5),Fiber Distributed Datalink Interface (FDDI) Asynchronous Transfer Mode(ATM), Wireless Ethernet (IEEE 802.11), or Bluetooth (IEEE 802.15.1).Note that computing devices may be desktop, server, portable, hand-held,set-top, or any other desired type of configuration. As used herein, thenetwork 240 includes network variations such as the public Internet, aprivate network within the Internet, a secure network within theInternet, a private network, a public network, a value-added network, anintranet, and the like. In certain embodiments, network 240 may alsocomprise a virtual private network (VPN).

The macro node 205 and/or either or both of the femto nodes 210 and 212may be connected to the network 240 using any of a multitude of devicesor methods. As described above, the femto node 210 may be connected tothe network 240 using an IP connection or other means. The macro node205 may be connected to the network 240 by similar means or by otherpublic, private, or proprietary means. The connections to the network240 may be wired or wireless. These connections, which connect the macronode 205 and/or either or both of the femto nodes 210 and 212 to thenetwork 240, which may be referred to as the “backbone” of the network,may be referred to as the backhaul. Devices such as a radio networkcontroller (RNC), base station controller (BSC), or another device orsystem (not shown) may be used to manage communications between two ormore macro nodes, pico nodes, and/or femto nodes. In some embodiments,messages are communicated over the backhaul utilizing a radio accessnetwork application part (RANAP) protocol. In one embodiment, messagesare communicated over the backhaul utilizing an radio access networkinformation management (RIM) procedure. Those of skill in the art willappreciate other devices and methods for communicating with the network240.

FIG. 3 illustrates exemplary coverage areas of the wirelesscommunication networks 100 and 200 shown in FIGS. 1 and 2. The coveragearea 300 may comprise one or more geographical areas in which the UE 220may access the communication network 240 as discussed above with respectto FIG. 2. As shown the coverage area 300 comprises several trackingareas 302 (or routing areas or location areas). Each tracking area 302comprises several macro areas 304, which may be similar to the macroarea 230 described above with respect to FIG. 2. Here, areas of coverageassociated with tracking areas 302A, 302B, and 302C are shown asdelineated by wide lines as and the macro areas 304 are represented byhexagons. The tracking areas 302 may also comprise femto areas 306,which may be similar to the femto area 230 described above with respectto FIG. 2. In this example, each of the femto areas 306 (e.g., femtoarea 306C) is depicted within a macro area 304 (e.g., macro area 304B).It should be appreciated, however, that a femto area 306 may not lieentirely within a macro area 304. In practice, a large number of femtoareas 306 may be defined with a given tracking area 302 or macro area304. Also, one or more pico areas (not shown) may be defined within agiven tracking area 302 or macro area 304.

Referring again to FIG. 2, the owner of the femto node 210 may subscribeto a mobile service, such as, for example, 3G mobile service, offeredthrough the communication network 240 (e.g., a mobile operator corenetwork). In addition, a user equipment 221 may be capable of operatingboth in macro environments (e.g., macro areas) and in smaller scale(e.g., residential, femto areas, pico areas, etc.) network environments.In other words, depending on the current location of the user equipment221, the user equipment 221 may access the communication network 240 bya macro node 205 or by any one of a set of femto nodes (e.g., femtonodes 210, 212). For example, when a subscriber is outside his home, hemay be served by a macro node (e.g., node 205) and when the subscriberis at home, he may be served by a femto node (e.g., node 210). It shouldfurther be appreciated that the femto nodes 210 may be backwardcompatible with existing user equipments 221.

The femto node 210 may communicate over a single frequency or, in thealternative, over multiple frequencies. Depending on the particularconfiguration, the single frequency or one or more of the multiplefrequencies may overlap with one or more frequencies used by a macronode (e.g., node 205).

In one embodiment, a user equipment 221 may be configured to connect toa particular (e.g., preferred) femto node (e.g., a home femto node ofthe user equipment 221) whenever the user equipment 221 is withincommunication range of the femto node. For example, the user equipment221 may communicate with only the femto node 210 when the user equipment221 is within the femto area 215.

In another embodiment, the user equipment 221 is communicating with anode but is not communicating with a preferred node (e.g., as defined ina preferred roaming list). In this embodiment, the user equipment 221may continue to search for a preferred node (e.g., the preferred femtonode 210) using a Better System Reselection (“BSR”). The BSR maycomprise a method comprising a periodic scanning of available systems todetermine whether better systems are currently available. The BSR mayfurther comprise attempting to associate with available preferredsystems. The user equipment 221 may limit the BSR to scanning over oneor more specific bands and/or channels. Upon discovery of a preferredfemto node 210, the user equipment 221 selects the femto node 210 forcommunicating with to access the communication network 240 within thefemto area 215.

For example, when the UE 221, which may be communicating with the macronode 205, gets close to the femto node 210, it may handoff (i.e., idleor active handoff) to the femto node 210. Accordingly, the UE 222 beginscommunicating with the femto node 210. In mobile networks such as 1xRTT,1xEV-DO, WCDMA, HSPA, etc., when a user equipment gets close to a node,there are mechanisms to trigger the handoff. Conditions of the networkthat trigger the handoff may be referred to as handoff conditions. Forexample, each node (e.g., femto node, macro node, etc.) may beconfigured to generate and transmit a beacon. The beacon may comprisepilot channels and other overhead channels. Further, the beacon may betransmitted on multiple frequencies such that UEs operating on differentfrequencies can detect the beacon. The UE may use the beacon receivedfrom a node to identify the node, for example for purposes of performinga handoff when a handoff condition is identified.

In some embodiments, a UE may uniquely identify a femto node bydetecting a beacon or pilot signal transmitted from the femto node. Inone embodiment, the beacon transmitted from one or more femto nodescomprises pilot signals of the femto node. The pilot signals mayuniquely identify the femto node from which they were transmitted. Forexample, femto nodes 210 and 212 may each transmit a different pilotsignal. The UE 221 may receive both pilot signals from each of the femtonodes 210 and 212. In some embodiments, the UE 221 may generate a pilotstrength measurement report (PSMR), or other indicator of signalquality. The PSMR may comprise the received pilot signals. The PSMR mayfurther comprise the signal strength (E_(cp)/I_(o)) of the pilotsignals. The UE 221 may transmit the PSMR in a measurement reportmessage (MRM) to the macro node 205 with which it is communicating, orto one or both of the femto nodes 210 and 212, as will be described inadditional detail below.

In one embodiment, a node may only provide certain services to certainuser equipments with which it is provisioned to communicate. Such a nodemay be referred to as a “restricted” or “closed” node. In wirelesscommunication networks comprising restricted femto nodes, a given userequipment may only be served by macro nodes and a defined set of femtonodes (e.g., the femto node 210). In other embodiments, a node may berestricted to not provide at least one of: signaling, data access,registration, paging, or service.

In one embodiment, a restricted femto node (which may also be referredto as a Closed Subscriber Group Home NodeB) is one that provides serviceto a restricted provisioned set of user equipments. This set may betemporarily or permanently changed to include additional or fewer userequipments as necessary. In some aspects, a Closed Subscriber Group(“CSG”) may be defined as the set of access nodes (e.g., femto nodes)that share a common access control list of user equipments (e.g., a listof the restricted provisioned set of user equipments). A channel onwhich all femto nodes (or all restricted femto nodes) in a regionoperate may be referred to as a femto channel.

Various relationships may thus exist between a given femto node and agiven user equipment. For example, from the perspective of a userequipment, an open femto node may refer to a femto node with norestricted association. A restricted or closed femto node may refer to afemto node that is restricted in some manner (e.g., restricted forassociation and/or registration). A hybrid femto node may refer to afemto node where a limited amount of the femto nodes resources areavailable to all users, while the rest are operated in a restrictedmanner. A home femto node may refer to a femto node on which the userequipment is subscribed to/authorized to access and operate on. A guestfemto node may refer to a femto node on which a user equipment istemporarily subscribed to/authorized to access or operate on. An alienfemto node may refer to a femto node on which the user equipment is notauthorized to access or operate on, except for perhaps emergencysituations (e.g., 911 calls).

From a restricted femto node perspective, a home user equipment mayrefer to a user equipment that is subscribed to/authorized to access therestricted femto node. A guest user equipment may refer to a userequipment with temporary subscription/access to the restricted femtonode. An alien user equipment may refer to a user equipment that doesnot have permission to access the restricted femto node, except forperhaps emergency situations, such as 911 calls.

For convenience, the disclosure herein describes various functionalitiesrelated to a femto node. It should be appreciated, however, that a piconode may provide the same or similar functionality for a larger coveragearea. For example, a pico node may be restricted, a home pico node maybe defined for a given user equipment, and so on.

A wireless multiple-access communication system may simultaneouslysupport communication for multiple wireless user equipments. Asmentioned above, each user equipment may communicate with one or morenodes via transmissions on the forward and reverse links. The forwardlink (or downlink) refers to the communication link from the node to theuser equipment, and the reverse link (or uplink) refers to thecommunication link from the user equipment to the node. Thiscommunication link may be established via a single-in-single-out system,a multiple-in-multiple-out (“MIMO”) system, or some other type ofsystem.

A MIMO system employs multiple (NT) transmit antennas and multiple (NR)receive antennas for data transmission. A MIMO channel formed by the NTtransmit and NR receive antennas may be comprise NS independentchannels, which are also referred to as spatial channels, where NS≦min{NT, NR}. Each of the NS independent channels corresponds to adimension. The MIMO system may provide improved performance (e.g.,higher throughput and/or greater reliability) if the additionaldimensionalities created by the multiple transmit and receive antennasare utilized.

A MIMO system may support time division duplex (“TDD”) and frequencydivision duplex (“FDD”). In a TDD system, the forward and reverse linktransmissions are on the same frequency region so that the reciprocityprinciple allows the estimation of the forward link channel from thereverse link channel. This enables a device (e.g., a node, a userequipment, etc.) to extract a transmit beam-forming gain on the forwardlink when multiple antennas are available at the device.

The teachings herein may be incorporated into a device (e.g., a node, auser equipment, etc.) employing various components for communicatingwith at least one other device.

FIG. 4 is a functional block diagram of a first exemplary femto node 410and a first exemplary user equipment 450 in one of the communicationnetworks of FIG. 2. As shown, a MIMO system 400 comprises a femto node410 and a user equipment 450 (e.g., the UE 222). At the femto node 410,traffic data for a number of data streams is provided from a data source412 to a transmit (“TX”) data processor 414.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. The TX data processor 414 formats, codes, andinterleaves the traffic data for each data stream based on a particularcoding scheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by a processor 430. A data memory 432 may storeprogram code, data, and other information used by the processor 430 orother components of the femto node 410.

The modulation symbols for all data streams are then provided to a TXMIMO processor 420, which may further process the modulation symbols(e.g., for OFDM). The TX MIMO processor 420 then provides NT modulationsymbol streams to NT transceivers (“XCVR”) 422A through 422T. In someaspects, the TX MIMO processor 420 applies beam-forming weights to thesymbols of the data streams and to the antenna from which the symbol isbeing transmitted.

Each transceiver 422 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. NTmodulated signals from transceivers 422A through 422T are thentransmitted from NT antennas 424A through 424T, respectively.

At the user equipment 450, the transmitted modulated signals arereceived by NR antennas 452A through 452R and the received signal fromeach antenna 452 is provided to a respective transceiver (“XCVR”) 454Athrough 454R. Each transceiver 454 conditions (e.g., filters, amplifies,and downconverts) a respective received signal, digitizes theconditioned signal to provide samples, and further processes the samplesto provide a corresponding “received” symbol stream.

A receive (“RX”) data processor 460 then receives and processes the NRreceived symbol streams from NR transceivers 454 based on a particularreceiver processing technique to provide NT “detected” symbol streams.The RX data processor 460 then demodulates, deinterleaves, and decodeseach detected symbol stream to recover the traffic data for the datastream. The processing performed by the RX data processor 460 iscomplementary to that performed by the TX MIMO processor 420 and the TXdata processor 414 at the femto node 410.

A processor 470 may periodically determine a pre-coding matrix to use.The processor 470 may formulate a reverse link message comprising amatrix index portion and a rank value portion. A data memory 472 maystore program code, data, and other information used by the processor470 or other components of the user equipment 450.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 438. TheTX data processor 438 also receives traffic data for a number of datastreams from a data source 436. The modulator 480 modulates the datastreams. Further, the transceivers 454A through 454R condition the datastreams and transmit the data streams back to the femto node 410.

At the femto node 410, the modulated signals from the user equipment 450are received by the antennas 424. Further, the transceivers 422condition the modulated signals. A demodulator (“DEMOD”) 440 demodulatesthe modulated signals. A RX data processor 442 processes the demodulatedsignals and extracts the reverse link message transmitted by the userequipment 450. The processor 430 may then determine which pre-codingmatrix to use for determining the beam-forming weights. Further, theprocessor 430 processes the extracted message.

Further, the femto node 410 and/or the user equipment 450 may compriseone or more components that perform interference control operations astaught herein. For example, an interference (“INTER”) control component490 may cooperate with the processor 430 and/or other components of thefemto node 410 to send/receive signals to/from another device (e.g., theuser equipment 450) as taught herein. Similarly, an interference controlcomponent 492 may cooperate with the processor 470 and/or othercomponents of the user equipment 450 to send/receive signals to/fromanother device (e.g., the femto node 410). It should be appreciated thatfor each of the femto node 410 and the user equipment 450 thefunctionality of two or more of the described components may be providedby a single component. For example, a single processing component mayprovide the functionality of the interference control component 490 andthe processor 430. Further, a single processing component may providethe functionality of the interference control component 492 and theprocessor 470.

FIG. 5 is a functional block diagram of a second exemplary femto node210 in one of the communication networks of FIG. 2. As described above,the femto node 210 may comprise an implementation of a node 104described with respect to FIG. 1, may be implemented in the network 300as described with respect to FIG. 3, and/or may be implemented accordingto the femto node 410 described with respect to FIG. 4. Although thefollowing description will be made with respect to the femto node 210,those of skill in the art will understand that the femto nodeillustrated in FIG. 5 and described with respect thereto mayadditionally or instead be implemented in the femto node 212.

The femto node 210 may comprise a transmitting module 502. Thetransmitting module 502 may be configured to transmit data to one ormore user devices. For example, the transmitting module 502 may beconfigured to transmit data from the data source 412, data stored in astoring module 504, or some other source, to the user equipment 222. Insome embodiments, the transmitting module 502 is configured to transmitdata to another node, for example the femto node 212 and/or the macronode 205. The transmitting module 502 may be configured to transmit datawirelessly, for example as illustrated in FIG. 2, and/or over a wirednetwork.

The transmitting module 502 may further be configured to broadcast abeacon or a pilot signal, for example as described above. The beacon orpilot signal may be broadcast over a plurality of channels, or may bebroadcast over a dedicated channel, for example a common pilot channel(CPICH). The power with which the pilot, or any other communicationssuch as user data or any other signals, is broadcast or transmitted maybe determined and adjusted by a power adjusting unit 506 incommunication with the transmitting module 502.

The transmitting module 502 may be implemented using one of or acombination of the transmitter portions of one or more of thetransceivers 422A-422T, the TX data processor 414, the TX MIMO processor420, and the processor 430. In some embodiments, the transmitting module502 comprises an antenna and a transceiver. The transceiver may beconfigured to modulate outbound wireless messages going to the UE 222.The messages may be transmitted via the antenna, for example one or moreof the antennas 424A-424T. The antenna may be configured to communicatewith the UE 222 over one or more carriers and one or more channels. Thewireless message may comprise voice and/or data-only information. Insome embodiments, the transmitting module 502 is configured to transmitcommunications over a wired connection. The transmitting module 502 mayfurther comprise a modem. The modem may be configured to modulate theoutbound wired messages going to the network 240.

As discussed above, the storing module 504 may be configured to storedata for transmission. The storing module 504 may also be configured tostore other data or information, for example system parameters orcontrol information. Stored data or information may comprise anycombination of information, bits, symbols, or other data orrepresentations. The storing module 506 may be implemented using thememory 432 described above with respect to FIG. 4. In some embodiments,the storing module 504 comprises a data buffer or a memory array, orother data structure, configured to store data. The storing module 504may comprise a plurality of these elements as well. If the storingmodule 504 is configured to store data to transmit, the storing module504 may receive the data from a number of sources. For example, the datamay be generated by or received from the data source 412 and/or theprocessor 430 described with respect to FIG. 4, or may be derived inpart from received information, for example as received using one ormore of the transceivers 422A-422T.

The storing module 504 may comprise processing module cache, including amulti-level hierarchical cache in which different levels have differentcapacities and access speeds. The storing module 504 may also compriserandom access memory (RAM), other volatile storage devices, ornon-volatile storage devices. The storage may include hard drives,optical discs, such as compact discs (CDs) or digital video discs(DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.

As discussed above, the power adjusting module 506 may be configured toadjust a power with which a signal is transmitted from the transmittingmodule 502. The power adjusting module 506 may be configured to adjustthe power based at least in part on information received using areceiving module 508, for example information indicative of ameasurement derived from reception of a signal transmitted using thetransmitting module 502 or an associated statistic. The power adjustingmodule 506 may further be configured to adjust the power based oninformation determined by a network listen module 510.

In some embodiments, the power adjusting module 506 adjusts the powerthat is used to transmit a signal from the transmitting module 502 suchthat the signal may be properly received throughout the femto area 215.This may be determined based on, for example, information indicative ofa path loss of the signal or of a strength of the signal. In someembodiments, the power adjusting module 506 further adjusts the powerthat is used to transmit the signal from the transmitting module 502such that the signal does not interfere with a UE that receivescommunications from the macro node 205 and the femto node 212. Thus, thepower adjusting module 506 may be configured to increase or decrease apower used to transmit a signal using the transmitting module 502 toincrease the likelihood of the signal being received throughout thefemto area 215 without interfering with the reception of signals atlocations external to the femto area 215.

Those of skill in the art will appreciate various circuits, chips,modules, and/or components, which may comprise either software orhardware or both, that may be used to implement the power adjustingmodule 506. The power adjusting module 506 may be partially or whollyimplemented in the processor 430 illustrated in FIG. 4.

The receiving module 508 may be configured to receive data from one ormore UEs. For example, the receiving module 508 may be configured toreceive data from the UE 222 illustrated in FIG. 2. In some embodiments,a UE that is communicating via the femto node 210 may be referred to asa home user equipment (HUE), and a UE that is communicating via anyfemto node, for example the femto node 210 and/or the femto node 212,may be referred to as a femto user equipment. In some embodiments, thereceiving module 506 is configured to receive a signal from anothernode, for example the femto node 212 and/or the macro node 205. In someembodiments, the receiving module 508 is configured to receive astatistic, for example from the femto node 212 and/or the macro node205. The receiving module 508 may be configured to receive datawirelessly, for example as illustrated in FIG. 2, and/or over a wirednetwork.

In one embodiment, the receiving module 508 is configured to receive abroadcast beacon or pilot signal. As described above, the beacon orpilot signal may be broadcast over a plurality of channels, or may bebroadcast over a dedicated channel, for example a common pilot channel(CPICH). The receiving module 508 may be implemented using one of or acombination of the receiver portions of one or more of the transceivers422A-422T, the demodulator 440, the RX data processor 442, and theprocessor 430. In some embodiments, the receiving module 508 comprisesan antenna and a transceiver. The transceiver may be configured todemodulate inbound wireless messages coming from the UE 222. Themessages may be received via the antenna. The antenna may be configuredto communicate with the UE 222 over one or more carriers and one oremore channels. The wireless message may comprise voice and/or data-onlyinformation. The receiving module 508 may demodulate the data received.In some embodiments, the receiving module 508 is configured to receivecommunications over a wired connection. The receiving module 508 mayfurther comprise a modem. The modem may be configured to demodulate theinbound wired messages coming from the network 240.

The network listen module 510 may be configured to measure signalsreceived by the receiving module 508, or to detect a condition of awireless network at the femto node 210. In some embodiments, the networklisten module 510 is configured to identify a WCDMA, GSM, TD-SCDMA, orother network based on the received signals. In some embodiments, thenetwork listen module 510 is referred to as a “sniffer.” Those of skillin the art will appreciate various circuits, chips, modules, and/orcomponents, which may comprise either software or hardware or both, thatmay be used to implement the network listen module 510. The networklisten module 510 may be partially or wholly implemented in theprocessor 430 illustrated in FIG. 4.

In previously known systems, a receiver of a femto node would beconfigured to receive signals, for example beacon signals, from a macronode serving a macro area in which the femto node is located. In thenetwork 200 illustrated in FIG. 2, the receiver would receive beaconstransmitted by the macro node 205. These received beacons would bepassed to a network listen module of the femto node, which would measurethe strength of a pilot of the beacon. Using the measurements of thebeacon transmitted from the macro node 205 and determined in the networklisten module, a power for transmitting signals would be determinedThus, in known systems, the transmission power of the femto node wouldbe adjusted to reduce interference based on signals received from anearby macro node. These received signals would be interpreted by thefemto node as being indicative of a network environment in which thefemto node is operating. Those of skill in the art will appreciate thatpilot signals may be received independent of a beacon signal. In someconfigurations of the network 200, both pilot signals and beacons areutilized. In other configurations of the network 200, only pilot signalsare utilized.

Determining a transmission power from a beacon received from a macronode may, however, be insufficient in many situations. For example, whena femto node is placed near a window of a house in a previously knownsystem, the network listen module may detect a higher interference atthe window than exists inside the house. If a UE that the femto nodecommunicates with is located inside the house, then the femto node wouldtransmit signals with a power that is greater than necessary because thefemto node would try to overcome the interference detected at thewindow. Transmitting with this unnecessarily high power may increase thearea in which signals from the femto node are received. Increasing thearea in this way may cause the signals from the femto node to leakoutside of the intended coverage area inside the house and interferewith UEs that are not communicating with the femto node. Further,transmitting with this unnecessarily high power may decrease theavailable operating time of a femto node that is powered by a battery oranother independent power source.

As another example, when a femto node is located in basement of a housein a previously known system, the network listen module may detect alower interference in the basement than exists inside the remainder ofthe house. If a UE that the femto node communicates with is located at adistance from the basement, then the femto node would transmit signalswith a power that is lower than required because the femto node woulddetermine that the UE also experiences low interference. Transmittingwith this reduced power will may decrease the area in which signals fromthe femto node are received, which may result in insufficient receptionof signals transmitted from the femto node. In this situation, it may bepossible for the femto node to transmit at a higher power to ensureproper reception while still maintaining a transmission power that doesnot adversely interfere with UEs that are not communicating with thefemto node.

In some embodiments described herein, on the other hand, the femto node210 is configured to receive, for example using the receiving module508, information indicative of a measurement of a signal transmitted,for example using the transmitting module 502, from the femto node 210.This information may be received, for example, from a UE located in thefemto area 215 such as the UE 222. The information may be used by thepower adjusting module 506 to adjust the transmission power of thesignal. In this way, the femto node 210 may utilize information from UEsreceiving the signal in the femto area 215. In some embodiments, thefemto node 210 may receive similar information from another femto nodewhich receives and measures the signal, for example the femto node 212.

In some embodiments, information indicative of a measurement of a signaltransmitted from the femto node 210 may be communicated to a remotefemto node from a receiving UE. For example, when the UE 221 is locatednear the border of the femto area 217, in close proximity to the femtoarea 215, the UE 221 may detect a signal from the femto node 210 andtransmit information indicative of a measurement of that signal to thefemto node 212. The femto node 212 may then transmit the informationdirectly to the femto node 210, for example over a wired or wirelesslink, or may transmit the information to the femto node 210 via thenetwork 240 and/or the macro node 205. In one embodiment, the femto node212 determines a statistic based on communications from a plurality ofUEs regarding a signal transmitted by the femto node 210, and transmitsthe statistic to the femto node 210.

In some embodiments, information indicative of a measurement of a signaltransmitted from the femto node 210 may similarly be communicated to amacro node from a receiving UE. For example, when the UE 220 is locatedin close proximity to the femto area 215, the UE 220 may detect a signalfrom the femto node 210 and transmit information indicative of ameasurement of that signal to the macro node 205. The macro node 205 maysimilarly transmit the information to the femto node 210, for exampledirectly or indirectly through the backhaul, and via a wired or wirelesslink. In one embodiment, the macro node 205 determines a statistic basedon communications from a plurality of UEs regarding a signal transmittedby the femto node 210, and transmits the statistic to the femto node210.

In some embodiments, information indicative of a measurement of a signaltransmitted from the macro node 205 may be communicated to the femtonode 210. This information may be transmitted from to the femto node 210from a UE being served by the femto node 210. For example, when the UE222 is near the periphery of the femto area 215, it may receive signalsfrom the macro node 205 and communicate information indicative of ameasurement of the signals to the femto node 210. The information mayinstead be transmitted to the macro node 205, for example by the UE 220when the UE is near the periphery of the femto area 215, andcommunicated to the femto node 210 thereafter. This measurement of asignal of the macro node 205 may be used by the femto node 210 to moreaccurately determine network conditions, for example at the periphery ofthe femto area 215. Thus, the femto node 210 may be able to moreaccurately determine the environment throughout the femto area 215instead of making assumptions based solely on measurements made in thenetwork listen module 510.

Continuing to refer to FIG. 5, the femto node 210 may further comprise aregistration unit 512. The registration unit 512 may compriseinformation identifying one or more UEs permitted to communicate usingthe femto node 210. In one embodiment, the UEs identified by informationin the registration unit 512 comprise a CSG, as discussed above, or aClosed User Group (CUG). For a closed femto node, only UEs identified inthe registration unit 512 are permitted to communicate with other UEsthrough use of the transmitting module 502 and the receiving module 508.Thus, although UEs in the macro area 230 and/or the femto area 217 maydetect signals transmitted by the femto node 210 and may requestregistration with the femto node 210, these UEs will not be allowed toregister with the femto node 210 unless they are identified in theregistration unit 512.

In some embodiments, the registration unit 512 may be implemented as aportion of the storing module 504, or vice versa. In other embodiments,the registration unit 512 operates in conjunction with the storingmodule 504, for example identifying registered UEs based at least inpart on information stored in the storing module 504. Informationidentifying the UEs in the registration module may comprise anycombination of data, bits, symbols, or other information orrepresentations. The registration unit 512 may be implemented using thememory 432 described above with respect to FIG. 4. In some embodiments,the registration unit 512 comprises a data buffer or a memory array, orother data structure, configured to store data. For example, theregistration unit 512 may comprise a table storing a unique identifieror device ID for the registered UEs. The device ID may comprise anynumber of identifiers that may be used to identify an apparatus. Forexample, the device ID may comprise a serial number, a telephone number,a mobile identification number (MIN), an electronic serial number (ESN),an international mobile equipment identifier (IMEI), an internationalmobile subscriber identifier (IMSI), or any other identifier that may beused to identify an apparatus. The registration unit 512 may comprise aplurality of these elements as well.

The registration unit 512 may comprise processing module cache,including a multi-level hierarchical cache in which different levelshave different capacities and access speeds. The registration unit 512may also comprise random access memory (RAM), other volatile storagedevices, or non-volatile storage devices, and/or processing circuitryconfigured to identify UEs or determine that a UE is not identified inthe registration unit. For example, the registration unit 512 maycomprise the processor 430 or a portion thereof. Storage in theregistration unit 512 may include hard drives, optical discs, such ascompact discs (CDs) or digital video discs (DVDs), flash memory, floppydiscs, magnetic tape, and Zip drives.

In some embodiments, the femto node 210 is configured to adjust atransmission power based on unsuccessful registration attempts. Forexample, a request for registration may be received from a UE, forexample by the receiving module 508. After determining that the UE isnot registered with the femto node 210, for example by using theregistration unit 512, the transmission power may be adjusted, forexample by using the power adjusting module 506. In some embodiments, apower for transmitting a signal using the transmitting module 502 isadjusted by the power adjusting module 506 based on a plurality ofreceived requests for registration from UEs not identified in theregistration unit 512, or based on a statistic calculated therefrom. Insome situations, the improper registration attempts are an indication ofexcessive interference, for example at a periphery of the femto area215. As an example, if a number of UEs that are not registered with thefemto node 210 request service from the femto node 210, then these UEsmay be identifying the femto node 210 as the strongest transmissionsource and the femto node 210 may be transmitted with a power that istoo great.

FIG. 6 is a functional block diagram of a second exemplary userequipment 222 in one of the communication networks of FIG. 2. Asdescribed above, the UE 222 may comprise an implementation of a node 106described with respect to FIG. 1, and/or may be implemented according tothe UE 450 described with respect to FIG. 4. Although the followingdescription will be made with respect to the UE 222, those of skill inthe art will understand that the UE illustrated in FIG. 6 and describedwith respect thereto may additionally or instead be implemented ineither or both of the UEs 220 and 221.

The UE 222 may comprise a receiving module 602. The receiving module maybe configured to receive a signal from a femto node and/or a macro node.For example, the receiving module 602 may be configured to receive asignal from the femto node 210 and/or the macro node 205 illustrated inFIG. 2. The signal may comprise a beacon or pilot, as described above,or may comprise data being transmitted to the UE 222. As describedabove, the beacon or pilot signal may be received over a plurality ofchannels, or may be received over a dedicated channel, for example acommon pilot channel (CPICH). Similarly, data may be received over oneor more channels. The signal may comprise voice data when the UE is inan active call, for example. The receiving module 602 may be configuredto receive data wirelessly, for example as illustrated in FIG. 2.

In one embodiment, the receiving module 602 is configured to receive abroadcast beacon or pilot signal. The receiving module 602 may beimplemented using one of or a combination of the receiver portions ofone or more of the transceivers 454A-454R, the RX data processor 460,and the processor 470. In some embodiments, the receiving module 602comprises an antenna and a transceiver. The transceiver may beconfigured to demodulate inbound wireless messages coming from the femtonode 210, the femto node 212, and/or the macro node 205. The messagesmay be received via the antenna. The antenna may be configured tocommunicate with the femto node 210, the femto node 212, and/or themacro node 205 over one or more carriers and one ore more channels. Thewireless message may comprise voice and/or data-only information. Thereceiving module 602 may demodulate the data received. In someembodiments, the receiving module 602 is configured to receivecommunications over a wired connection.

The UE 222 may further comprise a signal measuring module 604. Thesignal measuring module may be configured to compute a measurement of areceived signal, for example using the receiving module 602. In someembodiments, the signal measuring module 604 is configured to determinea strength, interference, path loss, and/or seepage of the signal. Forexample, the signal measuring module may be configured to determine areceived signal code power (RSCP) of the signal. In some embodiments,the signal measuring module 604 may be configured to compute ameasurement for a pilot signal. For example, the signal measuring module604 may be configured to compute an energy per chip versus totalreceived power spectral density (E_(c)/I_(o)) of the pilot signal. Thoseof skill in the art will appreciate various circuits, chips, modules,and/or components, which may comprise either software or hardware orboth, that may be used to implement the signal measuring module 604. Thesignal measuring module 604 may be partially or wholly implemented inthe processor 470 illustrated in FIG. 4.

The UE 222 may further comprise a registration module 606. Theregistration module may be configured to generate requests tocommunicate via a node or register with that node, for example the femtonode 210. The requests may be transmitted by a transmitting module 608.The registration module 606 may be configured to generate a registrationrequest when a hand-off is desired or when requesting service for thefirst time after the UE 222 is powered on. In some embodiments, theregistration module 606 determines a node from which to requestregistration based on a measurement from the signal measuring module604. For example, if signals from several nodes are received by thereceiving module 602, the registration module 606 may determine that theUE 222 should communicate via whichever node transmitted the signal thatwas received with the highest signal to noise ratio (SNR). If the UE 222is not currently communicating via the node transmitted the signal thatwas received with the highest SNR, then the registration module 606 maygenerate a request to register with that node. This identification of ahigher SNR may comprise a handoff condition, which handoff condition wasdiscussed above. Information indicative of a measurement of the signalfrom the signal measuring module 604 may be transmitted with therequest.

In some embodiments, the registration module 606 is configured togenerate a request to register with a node only if the registrationmodule 606 can identify that the UE 222 is allowed to communicate viathat node. In some embodiments, the UE 222 may be configured to store aset of allowed nodes, for example in a storing module 610, and theregistration module 606 may be configured to request registration with anode only if it can be identified as a node in the set of allowed nodes.For example, the set of allowed nodes may include femto node 210 and allmacro nodes. If the UE 222 is first located in the macro area 230 andlater enters the femto area 210, the registration module 606 mayidentify a signal from the femto node 210 and attempt to register withthe femto area 210. As another example, the femto node 212 may be aclosed femto node, and the UE 222 may not be part of the CSG for thefemto node 212. If the UE 222 were to move from the femto area 215 tothe femto area 217, the registration module 606 may refrain fromrequesting to communicate via the femto node 212 even if the receivingmodule 602 receives pilot signals from the femto node 212.

In some embodiments, the registration module 606 may be configured togenerate an interference communication to transmit to a node, forexample using the transmitting module 608, when an interferencecondition is detected. The interference condition may be determinedbased on a measurement from the signal measuring module 604. Forexample, an interference condition may be identified when a path loss ofa pilot signal from a home node of the UE 222 is above a thresholdbecause of interference from a signal being transmitted by another node.The interference communication may comprise an over-the-air (OTA)message addressed to the interfering node. In some embodiments, thiscommunication is only generated and/or transmitted when the registrationmodule 606 identifies that the UE 222 is not allowed to communicate viathe interfering node. The interference communication may be sent using arandom access channel (RACH) procedure, and may include an E_(c)/I_(o)or RSCP for a signal received from the interfering node. Those of skillin the art will appreciate that if the UE 222 is allowed to communicatevia the interfering node, then the UE 222 may simply register with theinterfering node and transmit an interference measure to the interferingmode during communication with the node. When the UE 222 is not allowedto communicate with the interfering node, however, a specialinterference communication could be sent to the interfering node withoutthe expectation that the interfering node would acknowledge thecommunication or otherwise direct communication to the UE 222.

The registration module 606 may identify and distinguish betweendifferent networks using any number of methods or techniques. In someembodiments, each pilot signal comprises a physical layer identifier,such as an offset pseudo noise (PN) short code, which may be used toidentify which node transmitted the pilot. In other embodiments, nodesmay be identified by a location area code (LAC). For example, each femtonode in the network 200 may be identified by a unique LAC. Macro nodesmay additionally be identified by unique LACs, or in some embodimentsmay share a LAC with one or more other macro nodes. Those of skill inthe art will appreciate other methods or techniques that may be used toidentify a transmitting node or a network of a transmitting node.

In some embodiments, in order to determine whether or not the UE 222 isallowed to access a femto node, the registration module 606 may read L3overhead messages such as system information broadcasts (SIBs) of thefemto node. These L3 overhead messages may be periodically broadcast bythe femto node and may be received using the receiving module 602. Thesystem information may include identity information such as a CSG IDand/or a cell ID, which uniquely identify the femto node. The systeminformation may further include an indicator of the access mode of thefemto node (e.g., closed, open, or hybrid). Accordingly, theregistration module 606 can determine whether it can access the femtonode and also how to uniquely identify the femto node. For example, thisinformation may be used in combination with a stored set of allowedfemto nodes or allowed cells.

Those of skill in the art will appreciate various circuits, chips,modules, and/or components, which may comprise either software orhardware or both, that may be used to implement the registration module606. The registration module 606 may be partially or wholly implementedin the processor 470 illustrated in FIG. 4.

As described above, the transmitting module 608 may be configured totransmit messages or communications, for example to a node such as thefemto node 210 and/or the macro node 205. As described above, thetransmitting module 608 may be configured to transmit request forregistration to a node and/or an interference communication. Thetransmitting module 608 may further be configured to transmit ameasurement from the signal measuring module 604 or informationindicative thereof. In some embodiments, the transmitting module may beconfigured to transmit data, and may be configured to transmitcommunications to another UE. The transmitting module 608 may beconfigured to transmit information from the signal measuring module 604,communications from the registration module 606, data stored in thestoring module 610, data from the data source 436, or some other source.The transmitting module 606 may be configured to transmit datawirelessly, for example as illustrated in FIG. 2.

The transmitting module 606 may be implemented using one of or acombination of the transmitter portions of one or more of thetransceivers 454A-454R, the modulator 480, the TX data processor 438,and the processor 470. In some embodiments, the transmitting module 606comprises an antenna and a transceiver. The transceiver may beconfigured to modulate outbound wireless messages going to the macronode 205, femto node 210, and/or femto node 212. The messages may betransmitted via the antenna, for example one or more of the antennas452A-452R. The antenna may be configured to communicate with the macronode 205, femto node 210, and/or femto node 212 over one or morecarriers and one or more channels. The wireless messages may comprisevoice and/or data-only information.

As described above, the storing module 610 may be configured to storedata for transmission, for example using the transmitting module 608.The storing module 610 may also be configured to store other data orinformation, for example information for identifying transmitting nodesor information regarding a set of nodes which the UE 222 is allowed toregister with or for identifying preferred nodes. In one embodiment,information for identifying a CSG to which the UE 222 belongs is storedin a table in the storing module 610. Stored data or information maycomprise any combination of information, bits, symbols, or other data orrepresentations. The storing module may be implemented using the memory472 described above with respect to FIG. 4. In some embodiments, thestoring module 610 comprises a data buffer or a memory array, or otherdata structure, configured to store data or information. The storingmodule 610 may comprise a plurality of these elements as well.

The storing module 610 may comprise processing module cache, including amulti-level hierarchical cache in which different levels have differentcapacities and access speeds. The storing module 610 may also compriserandom access memory (RAM), other volatile storage devices, ornon-volatile storage devices. The storage may include hard drives,optical discs, such as compact discs (CDs) or digital video discs(DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.

FIG. 7 a functional block diagram of an exemplary macro node 205 in oneof the communication networks of FIG. 2. As described above, the macronode 210 may comprise an implementation of a node 104 described withrespect to FIG. 1, and/or may be implemented in the network 300 asdescribed with respect to FIG. 3. In some embodiments, the macro node205 may be implemented using components similar to those described withrespect to the femto node 410 illustrated in FIG. 4.

The macro node 205 may comprise a receiving module 702. The receivingmodule 702 may be configured to receive data from one or more UEs. Forexample, the receiving module 702 may be configured to receive data fromthe UE 220 illustrated in FIG. 2. In some embodiments, a UE that is incommunication with the macro node 205 is referred to as a macro userequipment (MUE). The receiving module 702 may be configured to receiveinformation from the UE 220 indicative of a measurement of a signalreceived by the UE 220. For example, the information may include ameasurement of a quality of a pilot signal received by the UE 220 fromthe femto node 210. The measurement may include any signal measurementdiscussed above, for example when discussing the signal measuring module604 illustrated in FIG. 6. The receiving module 702 may be configured toreceive data wirelessly, for example as illustrated in FIG. 2, and/orover a wired network. In some embodiments, the receiving module 702 isconfigured to receive communications from a femto node, for example thefemto node 210 and/or 212, either directly or through the backhaul orthe network 240.

The receiving module 702 may be implemented using one of or acombination of elements similar to the receiver portions of one or moreof the transceivers 422A-422T, the demodulator 440, the RX dataprocessor 442, and the processor 430. In some embodiments, the receivingmodule 702 comprises an antenna and a transceiver. The transceiver maybe configured to demodulate inbound wireless messages coming from the UE220. The messages may be received via the antenna. The antenna may beconfigured to communicate with the UE 220 over one or more carriers andone ore more channels. The wireless message may comprise voice and/ordata-only information. The receiving module 702 may demodulate the datareceived. The receiving module 702 may further comprise a modem. Themodem may be configured to demodulate inbound wired messages coming fromthe network 240.

The macro node 205 may further comprise a statistic module 704. Thestatistic module 704 may be configured to calculate or determine astatistic from information received via the receiving module 702. Forexample, when the receiving module 702 receives a plurality ofcommunications regarding a measurement of a received signal, thestatistic module 704 may calculate an average measurement. In someembodiments, the statistic module 704 is configured to determine anumber of different devices from which the receiving module 702 receiveda measurement. For example, if the receiving module 702 received twomeasurements from the UE 220 and three measurements from the UE 221regarding reception of a signal from the femto node, the receivingmodule 702 may determine that a measurement was received from two uniqueUEs. Information for determining the statistic may be stored in astoring module 706. The statistic module 704 may be configured toaggregate information from a plurality of communications. For example, alist of all measurements received by the receiving module 702 over acertain time period may be aggregated by the statistic module 704.Although the following description will refer to a statistic calculatedby the statistic module 704, those of skill in the art will appreciatethat the following description may also apply to an aggregate of datacollected by the statistic module 704.

An average measurement, or other statistic, may be calculated at regularintervals or for specific periods of time. For example, the statisticmodule 704 may be configured to determine the mode of an SNR indicatedby all measurements received within the past hour. This measurement maybe calculated every hour, for example, or may be calculated onoccurrence of an identified event. For example, the statistic module 704may calculate an average signal quality from all measurements receivedwithin a specified time frame upon receipt of a request, for examplefrom a node transmitting the signal on which the measurements are based.The request may in some embodiments comprise the specified time frame.As another example, the statistic module 704 may determine when thenumber of received measurements has exceeded a threshold, and may thencalculate a statistic such as an average or a maximum measurement fromthose received measurements.

In some embodiments, the statistic module 704 is configured to maintaininformation, for example in the storing module 706, regarding severalother nodes. For example, the receiving module 702 may receiveinformation indicative of measurements calculated from signalstransmitted from both the femto node 210 and the femto node 212. Thestatistic module 704 may be configured to distinguish betweenmeasurements made for signals from each of these femto nodes, and todetermine a statistic for each node individually. Those of skill in theart will recognize that the statistic module 704 may in some embodimentsbe configured to calculate a statistic for several nodes in theaggregate as well, for example for the femto node 210 and the macro node205.

In some embodiments, measurements that do not satisfy a predeterminedcondition are not considered when calculating the statistic. Forexample, the statistic module 704 may be configured to determine anumber of devices that received a signal from the femto node 210 with anE_(c)/I_(o) above a certain threshold. Measurements indicating anEc/I_(o) below this threshold may be ignored by the statistic module704. Similarly, a statistic could be calculated from all measurementsindicating an SNR below a given threshold.

In some embodiments, the statistic module 704 may be configured todetermine a distribution. For example, the statistic module 704 may beconfigured to determine a number of unique devices that received asignal from femto node 210 having an RSCP in each of a plurality ofranges. Thus, the statistic module 704 might determine that threedevices reported receiving the signal with an RSCP of −100 dBm to −90dBm, six devices reported receiving the signal with an RSCP of −90 dBmto −80 dBm, and one device reported receiving the signal with an RSCP of−80 dBm to −70 dBm. In some embodiments, the statistic module 704 isconfigured to distinguish between the types of devices from which ameasurement is received by the receiving module 702. For example, in thedistribution discussed above, the statistic module 704 may determinethat the six devices which received the signal with an RSCP of −90 dBmto −80 dBm consisted of two femto nodes and four UEs. The statisticmodule 704 may be configured to distinguish between devices using anynumber of methods or techniques, for example by correlating a device IDwith a table of known device types.

Those of skill in the art will appreciate various circuits, chips,modules, and/or components, which may comprise either software orhardware or both, that may be used to implement the statistic module704. The statistic module 704 may be partially or wholly implemented inelements similar to the processor 430 illustrated in FIG. 4.

As described above, the storing module 706 may be configured to storeinformation received using the receiving module 702 and/or used by thestatistic module 704 to calculate or determine a statistic. The storingmodule 706 may further be configured to store data for transmission, forexample using a transmitting module 708. The storing module 708 may alsobe configured to store other data or information, as will be understoodby those of skill in the art. The storing module may be implementedusing elements similar to the memory 432 described above with respect toFIG. 4. In some embodiments, the storing module 706 comprises a databuffer or a memory array, or other data structure, configured to storedata or information. The storing module 706 may comprise a plurality ofthese elements as well.

The storing module 706 may comprise processing module cache, including amulti-level hierarchical cache in which different levels have differentcapacities and access speeds. The storing module 706 may also compriserandom access memory (RAM), other volatile storage devices, ornon-volatile storage devices. The storage may include hard drives,optical discs, such as compact discs (CDs) or digital video discs(DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.

As described above, the transmitting module 708 may be configured totransmit data, for example to the UE 220. The transmitting module 708may also be configured to transmit a statistic determined by thestatistic module 704 or information indicative thereof, for example to afemto node such as the femto node 210. In some embodiments, thetransmitting module 708 is configured to transmit messages over awireless link, for example to the UE 220. In some embodiments, thetransmitting module 708 is configured to transmit messages over a wiredlink, for example to the network 240. Messages may be communicated, forexample when being transmitted to a femto node such as the femto node210, via an RNC, and/or using a RANAP protocol. In one embodiment,messages are communicated over the backhaul utilizing a RIM procedure.In some previously known systems, there exist radio access network (RAN)mechanisms for communicating information between a Global System forMobile Communications (GSM) network and a Universal MobileTelecommunications System (UMTS) network. In some embodiments discussedherein, however, RAN mechanisms for communicating between two UMTSnetworks are described.

The transmitting module 708 may be implemented using one of or acombination of elements similar to the transmitter portions of one ormore of the transceivers 422A-422T, the TX data processor 414, the TXMIMO processor 420, and the processor 430. In some embodiments, thetransmitting module 708 comprises an antenna and a transceiver. Thetransceiver may be configured to modulate outbound wireless messagesgoing to the UE 220 or to the femto node 210. The messages may betransmitted via the antenna, for example antennas similar to one or moreof the antennas 424A-424T. The antenna may be configured to communicatewith the UE 220 or the femto node 210 over one or more carriers and oneor more channels. The wireless message may comprise voice and/ordata-only information. The transmitting module 708 may further comprisea modem. The modem may be configured to modulate outbound wired messagesgoing to the network 240.

FIG. 8 illustrates an exemplary method 800 of communication for a userequipment, for example the UE 222. Although the method 800 will bedescribed below with respect to elements of the UE 222, those of skillin the art will appreciate that other components may be used toimplement one or more of the steps described herein, and that the method800 may be practiced by other devices.

At step 802, a signal is received from a femto node. For example, thereceiving module 602 may receive a pilot signal or data communicationfrom the femto node 210. The signal may be wirelessly received, and maybe directed to the UE 222 or may be directed to another device and seenby the UE.

At step 804, a measurement is calculated, for example by the signalmeasuring module 604, based at least in part on the signal received atstep 804. The measurement may be any measurement as discussed above. Forexample, the measurement may comprise a PSMR, or an E_(c)/I_(o) or apilot received at step 804. The measurement may be indicative of ageneral signal quality or strength, or of a path loss of the receivedsignal. The measurement may include an SNR of the received signal orinformation indicative of seepage or fading of the signal. Those ofskill in the art will appreciate other measurements that may becalculated at step 804.

In some embodiments, the UE 222 calculates a statistic at step 804. Thestatistic may be similar to the statistic described above with respectto FIG. 7. For example, the signal measuring module 604 may beconfigured to calculate an average measurement from a plurality ofsignals received from the femto node 210 at the receiving module 602.Those of skill in the art will appreciate other statistics that may becalculated at step 804.

Continuing to step 806, information indicative of the measurementdetermined at step 804 is transmitted to a serving node of the UE 222.The serving node, which the UE 222 uses to communicate with otherdevices, may be the same as the femto node from which the UE 222received the signal at step 802, or may be a different node. Forexample, the UE 222 is illustrated in FIG. 2 as being located within thefemto area 215. While in the femto area 215, the UE 222 may becommunicating with the UE 221 by using the femto node 210 as the servingnode. The UE 222 may receive a pilot signal from the femto node 210 atstep 802, determine a measurement of the pilot at step 804, and transmitthe information indicative of the measurement back to the femto node 210at step 806.

As another example, there may be a situation where the UE 220 is locatednear the femto area 215. Although the UE 220 is using the macro node 205to communicate with other devices, the UE 220 may detect or receive asignal from the femto node 210. This may be referred to as “seeing” thefemto node 210. At step 804, the UE 220 calculates a measurement of thesignal from the femto node 210, and at step 806 the UE 220 transmitsinformation indicative of the measurement to the macro node 205.Similarly, when the UE 221 is located near the femto area 215, the UE221 may receive a pilot signal broadcast by the femto node 210 eventhough the UE 221 is in active communication with the femto node 212.The UE 221 may determine a measurement of the received pilot signal, andtransmit that measurement to the femto node 212.

The measurement or information indicative thereof may be wirelesslytransmitted to the serving node at step 806. Further, the informationmay be transmitted in any number of ways or using any number oftechniques. For example, the UE 222 may transmit an MRM having theinformation therein.

The determination of the measurement at step 804 and/or the transmissionat step 806 may be performed at any number of times, or may be triggeredin any number of ways. For example, information may be transmitted atstep 806 only when the measurement determined at step 804 is above acertain threshold. In some embodiments, information may be transmittedat step 806 only when signals received from the femto node 210 are belowa threshold for a predetermined number of times in a row. For example,if the UE 222 receives three pilot signals in a row from the femto node210 having an SNR below the threshold, the UE 222 may determine thelowest SNR or another statistic and transmit it to the femto node 210.

In another embodiment, the measurement could be determined at step 804and/or transmitted at step 806 at regular intervals. In someembodiments, the determination of the measurement and/or thetransmission are triggered by a predetermined event. For example, themeasurement may be determined at step 804 and transmitted at step 806 inresponse to a request received from the femto node 210. In someembodiments, steps 804 and 806 are performed when the UE 222 hands offfrom one node to another. In this situation, the UE 222 could send ameasurement to a node either immediately before handoff, or immediatelyafter. The measurement could be for a signal received from the oldserving node or for the new serving node. In some embodiments,information indicative of the measurement is transmitted at step 806when the UE 222 sees a femto node which is not currently serving the UE222.

Those of skill in the art will recognize that the method 800 may beperformed by the UE 222 when in an active mode, for example while in acall or while communicating user data. Thus, information may betransmitted at step 806 in conjunction with active transmission ofother. Those of skill in the art, however, will appreciate that in someembodiments the method 800 may be performed while in a passive mode.

Those of skill in the art will similarly recognize that the method 800may be used to receive a signal from a macro node at step 802, forexample using the receiving module 602 to receive a signal from themacro node 205. At step 804, a measurement of the signal may bedetermined, for example by the signal measuring module 604, and themeasurement transmitted at step 806, for example by the transmittingmodule 608. The measurement may be transmitted to the femto node 210 bythe UE 222, for example, or may be relayed to the femto node 210, forexample by the macro node 205 when the UE 220 transmits the measurement.In one embodiment, measurements from a macro node are transmitted to thefemto node when the UE hands off to the femto node from the macro node.In other embodiments, the femto node may request macro nodemeasurements, for example from a UE that can see both the femto node andthe macro node, or from the macro node itself. Those of skill in the artwill recognize other situations in which a macro node measurement may betransmitted to the femto node, for example at a determined interval orwhen the macro node determines it would be advantageous.

The method 800 may be performed similarly by devices other than the UE222. For example, a neighboring femto node may perform the method 800similar to how the UE 222 performs the method 800. In one embodiment,the method 800 is implemented by the femto node 212. At step 802, thefemto node 212 receives a signal from the femto node 210, for exampleusing the receiving module 508. At step 804, the femto node 212determines a measurement of the received signal. The femto node 212 mayuse the network listen module 510 to perform step 804, or the femto node212 may comprise a module similar to the signal measuring module 604described with respect to the UE 222. At step 806, the femto node 212may transmit information indicative of the measurement to the femto node210, for example using the transmitting module 502. In some embodiments,the transmission is directly to the femto node 210 via a wireless link.In some embodiments, the information is transmitted to a macro node, forexample the macro node 205, for transmission to the femto node 210.Those of skill in the art will appreciate that some embodiments of themacro node 205 may similarly be used to communicate informationindicative of a measurement to the femto node 210.

FIG. 9 illustrates an exemplary method 900 of communication for a node,for example the macro node 205. Although the method 900 will bedescribed below with respect to elements of the macro node 205, those ofskill in the art will appreciate that other components may be used toimplement one or more of the steps described herein, and that the method900 may be practiced by other devices.

At step 902, a measurement or information indicative thereof isreceived, for example using the receiving module 702. The measurement orinformation may be received from a UE, for example the UE 220, or fromanother node, for example the femto node 212. The measurement orinformation may be received directly from another device, for examplevia a wireless link, or may be received through the network 240, forexample through the backhaul.

At step 904, a statistic may be calculated, for example by the statisticmodule 704, if a plurality of measurements have been received. Thestatistic may comprise any of the statistics discussed above withrespect to FIG. 7, and may be calculated using any of the methods ortechniques described therein. For example, the statistic may becalculated as an average, a mode, a count or quantity, or adistribution. The statistic may be an ongoing calculation utilizing thecurrent measurement received at step 904 and past measurements, or thestatistic may be limited to a certain period of time. The period of timemay be established beforehand as a default period, or the period of timemay be periodically set or reset, for example by a request received fromthe femto node 210. Those of skill in the art will appreciate otherstatistics that may be calculated and other techniques that may be usedto determine the statistic at step 904.

At step 906, at least a portion of the information indicative of themeasurement or of the statistic is transmitted to a femto nodeassociated with the measurement. For example, if the macro node 205received a measurement at 902 of a signal transmitted by the femto node210, then the macro node 205 would transmit the measurement or astatistic derived from the measurement to the femto node 210 at step906. In some embodiments, a node identifier or cell ID is received withthe measurement at step 902. This information may be used to identifywhich femto node transmitted the signal which the measurement pertainsto. The identifying information may contain data identifying a pilotsignal or PN sequence that may be use to identify the appropriate femtonode or cell. Those of skill in the art will appreciate variousidentifiers and techniques of identifying a femto node or cell. In someembodiments, both the measurement received at step 902 and the statisticdetermined at step 904 are transmitted to the femto node at step 906.

Information indicative of the measurement or statistic may betransmitted to the femto node at step 906 in any number of ways. Forexample, as described above, the transmission may be directly to thefemto node, for example over a wireless channel. In one embodiment, themacro node 205 transmits information indicative of the measurement orstatistic wirelessly to the femto node 210. In other embodiments, thetransmission may be routed via an RNC, and/or using a RANAP protocol, asdescribed above. In one embodiment, information indicative of themeasurement or statistic is communicated over the backhaul utilizing aRIM procedure.

The determining of the statistic at step 904 and/or the transmitting atstep 906 may be performed under a variety of situations. Measurementsreceived at step 902, for example, may be individually forwarded to afemto node as soon as they are received, or a plurality of themeasurements may be gathered and forwarded to the femto node.

In some embodiments, the determining of the statistic at step 904 and/orthe transmitting at step 906 are performed at specific times or timeintervals. For example, the macro node 205 may collect all measurementsreceived during a day and store them in the storing module 706. At apredetermined time each day, for example during a control communicationtime or device update time at the end of the day or early in themorning, the macro node 205 may forward all of the measurements receivedthat day or may forward a statistic calculated therefrom. In otherembodiments, the macro node 205 may calculate a statistic from allmeasurements received in the past six hours at step 904, and transmitthat statistic at step 906.

In some embodiments, the determining of the statistic at step 904 and/orthe transmitting at step 906 are event driven. For example, thestatistic may be determined at step 904 and subsequently transmitted toa femto node at step 906 in response to a request from the femto node.In some embodiments, a statistic calculated at step 904 is onlytransmitted to the femto node when the measurement exceeds apredetermined threshold. Those of skill in the art will appreciate otherevents that may trigger the determining of the statistic at step 904and/or the transmission at step 906, or times other than those describedabove, or techniques other than those described herein.

Those of skill in the art will recognize that the method 900 may be usedto forward information indicative of a measurement of a signal from amacro node, for example the macro node 205. For example, informationindicative of a measurement of the signal may be received at step 902,for example from the UE 220 using the receiving module 702. At step 906,at least a portion of the information may be communicated to the femtonode 210, for example using the transmitting module 708.

The method 900 may be performed similarly by devices other than themacro node 205. For example, a neighboring femto node may perform themethod 900 similar to how the macro node 205 performs the method 900. Inone embodiment, the method 900 is implemented by the femto node 212. Atstep 902, the femto node 212 receives a measurement or informationindicative thereof from another device, for example from the UE 221, forexample using the receiving module 508. At step 904, the femto node maydetermine a statistic from the received measurement or information. Inthis embodiment, the femto node 212 may comprise a module similar to thestatistic module 704 described with respect to the macro node 205. Atstep 906, the femto node 212 transmits information indicative of themeasurement or the statistic to the femto node 210, for example. Theinformation indicative of the measurement or the statistic may betransmitted with the transmitting module 502. In some embodiments, thetransmission is directly to the femto node 210 via a wireless link. Insome embodiments, the information is transmitted to a macro node, forexample the macro node 205, for transmission to the femto node 210.Thus, the method 900 may be used by a plurality of nodes or devices toreceive and forward a measurement until that measurement is received bythe femto node corresponding to the measurement. In some embodiments,the measurement is forwarded between femto nodes and/or macro nodesuntil reaching its destination in a fashion that is similar to howpackets are forwarded in an internet protocol (IP) network. Themeasurements may also be forwarded to or from a UE.

FIG. 10 illustrates an exemplary method 1000 of adjusting a transmissionpower for a femto node, for example the femto node 210. Although themethod 900 will be described below with respect to elements of the femtonode 210, those of skill in the art will appreciate that othercomponents may be used to implement one or more of the steps describedherein, and that the method 900 may be practiced by other devices.

At step 1002, a signal is transmitted, for example using thetransmitting module 502. As described above, the signal may comprise apilot signal, and may be transmitted over one or more channels. Forexample, the signal may be a pilot signal transmitted over a CPICH. Insome embodiment, the signal encodes user or voice data.

At step 1004, a measurement of the signal or information indicative of ameasurement is received, for example by the receiving module 508. Themeasurement of information indicative thereof may be wirelessly receivedfrom a UE or node, for example the UE 222 or the femto node 212 or themacro node 205. In some embodiments, the measurement or informationthereof is received over a wired connection. In some embodiments, thetransmission may be received via an RNC, and/or using a RANAP protocol,as described above. In one embodiment, information indicative of themeasurement or statistic is received over the backhaul utilizing a RIMprocedure.

In some embodiments, step 1004 comprises receiving a statistic of aplurality of measurements instead of or in addition to the measurement.The statistic may be received using any of the methods or techniquesdescribed above.

Moving to step 1006, a transmission power is adjusted, for example toalter the power which the transmitting unit 502 uses to transmitsubsequent signals. The transmission power may be adjusted by the poweradjusting module 506, for example. In some embodiments, the transmissionpower is adjusted after receiving every measurement and/or statistic. Inother embodiments, the transmission power is adjusted after receiving apredetermined number of measurements and/or statistics. In someembodiments, the power is always adjusted at a predetermined interval orafter a certain event. Thus, the transmission power would increase ordecrease after every interval or event.

In other embodiments, the power adjusting module 506 may determinewhether to adjust the transmission power or not. For example, the poweradjusting module 506 may determine that no power adjustment is necessarywhen a received measurement and/or statistic is within a predeterminedrange. Thus, the transmission power of the femto node 210 may remainsubstantially static or consistent for a significant amount of time.

The transmission power of the transmitting module 502 may be adjustedbased on any of the statistics discussed above. For example, the femtonode 210 may receive a statistic from the macro node 205 indicating anaverage interference experienced by MUEs in the macro area 230 due tosignals being transmitted by the femto node 210. At step 1006, the poweradjusting module 506 may decrease the transmission power of the femtonode 210 if the average interference is higher than a first threshold.If the average interference is lower than a second threshold or thefemto node 210 doesn't receive any information regarding interferencewith MUEs, the power adjusting module 506 may increase the transmissionpower. The first and the second thresholds may be the same, or maydiffer in some embodiments.

In some embodiments, the power adjusting module 506 is configured toadjust the transmission power by a predetermined amount each time thetransmission power is changed. For example, when the femto node 210receives a measurement from the UE 222 indicating that an SNR determinedfrom a signal transmitted at step 1002 is lower than a threshold, thepower adjusting module 506 may increase the power by the predeterminedamount.

In some embodiments, the transmission power is adjusted in proportion toa difference between a received measurement and target measurement. Forexample, when the femto node 210 receives a measurement from the UE 222indicating that a signal quality of the signal transmitted at step 1002is lower than a target quality, the power adjusting module 506 mayincrease the power by an amount that is proportional to the differencebetween the measured signal quality and the target quality. Thus, theamount by which the power adjusting module 506 adjusts the transmissionpower may be determined as ΔP=a*(P_(Target)−P_(measured)), where a issome scaling factor. The factor a may be constant, or may be variedbased on received communications or varying environmental conditions,for example as determined by the network listen module 510.

In some embodiments, the femto node 210 may be configured to determineor estimate a range of the signals being broadcast at step 1002. Forexample, the femto node 210 may be configured to receive informationindicative of a path loss at step 1004, and may use the path lossinformation to estimate the size or coverage of the femto area 215.Based on this estimate, the power adjusting module 506 may change thetransmission power in an attempt to match the femto area 215 to adesired coverage area. In some embodiments, the desired coverage area isstatic. In other embodiments, the location of one or more UEs, forexample the UE 222, may be determined and the coverage area may be basedon that location. As another example, a transmission power of the femtonode 210 may be adjusted based on a distance from the transmittingmodule 502 where UEs registered with the femto node 210 are handing offto a different serving node.

The power may be adjusted using a short-term calibration scheme and/orusing a long-term calibration scheme. In one embodiment, a short-termcalibration scheme may include adjusting the transmission power toconform the measurement of a transmitted signal to a target measurement.For example, the target measurement may comprise a maximum interferenceof a specific UE being served by the femto node 210, for example the UE222. If the measurement received at step 1004 indicates that the UE 222is experiencing interference greater than the maximum interference whenreceiving a signal transmitted at step 1002, the power adjusting module506 may temporarily increase the transmission power. When the femto node210 receives another measurement indicating that the UE 222 is no longerexperiencing interference greater than the maximum interference, thepower adjusting module 506 may decrease the transmission power, forexample back to the previous power. Alternatively, the transmissionpower may be gradually increased according to a recovery schedule. Insome embodiments, the target measurement comprises a maximuminterference of a UE being served by a node other than the femto node210, for example the UE 220. In these embodiments, the power adjustingmodule 506 may temporarily decrease the transmission power in order toprotect the UE 220 from undue interference by the femto node 210 whenthe UE 220 is experiencing interference above the maximum interference.When the UE 220 is no longer experiencing interference greater than themaximum interference, the power adjusting module 506 may increase thetransmission power.

In one embodiment, a long-term calibration scheme may include adjustingthe default transmission power based on a measurement or statisticindicative of a period of time. For example, the femto node 210 mayreceive a statistic from the macro node 205 at step 1004 indicating aquantity of MUEs that saw the signal transmitted at step 1002 over thecourse of a day. If the quantity is greater than a threshold, the poweradjusting module 506 may adjust the default transmission power at step1006 so that transmissions the following day will begin with beingtransmitted at the new transmission power.

In some embodiments, a short-term calibration scheme and a long-termcalibration scheme may be combined. For example, the power adjustingmodule 506 may be configured to adjust the default transmission power ofthe transmitting module 502 if a short-term calibration scheme was usedmore than a maximum number of times in a twelve hour timeframe.

Those of skill in the art will appreciate other schemes, methods, andtechniques of adjusting the power at step 1006. Although the abovedescription of adjusting a transmission power described measurementsbased on a signal transmitted from the femto node 210, those of skill inthe art will appreciate that similar techniques may be used to adjustthe transmission power based on information indicative of measurementsof a signal received from the macro node 205. For example, a measurementof a strength of a pilot transmitted from the macro node 205 andreceived near the femto area 215 may be compared to a threshold. If themeasurement is below the threshold, the femto node 210 may determinethat interference with the macro node 205 isn't likely in the femto area215 and the power adjusting module 506 may increase the transmissionpower.

Continuing to step 1008, a signal is transmitted, for example by thetransmitting unit 502, using the adjusted power from step 1006. Thetransmitting may comprise sending a signal similar to the signaltransmitted at step 1002, for example sending a second pilot with theadjusted power if the measurement received at step 1004 pertained to afirst pilot transmitted at step 1002. In some embodiments, the signaltransmitted at step 1008 may be a different type of signal thantransmitted at step 1002. For example, the signal transmitted at step1002 may comprise a pilot signal, and the signal transmitted at step1008 may comprise a signal encoding user data. The signal may bewirelessly transmitted at step 1008, and may be transmitted to anynumber of devices, for example the UE 222, the femto node 212, and/orthe macro node 205. The signal may also be broadcast at step 1008 suchthat it may be received by any device in the femto area 215.

FIG. 11 illustrates another exemplary method 1100 of communication for auser equipment, for example the UE 221. Although the method 1100 will bedescribed below with respect to elements of the UE 221, those of skillin the art will appreciate that other components may be used toimplement one or more of the steps described herein, and that the method1100 may be practiced by other devices.

At step 1102, a signal is received from a femto node. For example, atstep 1102, the receiving module 602 may see a pilot signal or datacommunication from the femto node 210. At the time of receiving thesignal at step 1102, the femto node from which the signal was receivedmay not be the UE 221's serving node.

At step 1104, a condition is identified based on the signal received atstep 1102. In some embodiments, the condition comprises an interferencecondition. The interference condition may comprise any of the conditionsdiscussed above with respect to FIG. 6. In some embodiments, thecondition comprises a handoff condition. As described above, the handoffcondition may comprise the identification of a SNR of the signalreceived at step 1102 that is higher than an SNR of a pilot signalreceived from the serving node. The interference condition and thehandoff condition may be similar, or in some embodiments may bedifferent.

Moving to step 1106, a request for registering with the femto node fromwhich the signal was received at step 1102 may be transmitted to thefemto node. For example, if the UE 221 identifies a handoff condition atstep 1104 due to a pilot received from the femto node 210, the UE 221may attempt to register with the femto node 210. The request forregistration may be generated and/or transmitted as described above withrespect to FIG. 6. In some embodiments of the UE 221, the UE 221 may beconfigured to request registration with the femto node regardless ofwhether the UE 221 is permitted to register with the femto node. Forexample, some embodiments of the UE 221 may not be configured withfunctionality to determine whether the UE 221 may register with anygiven femto node.

At step 1108, an appropriately configured UE 221 may determine whetherto request registration. This determination may be based on whether thecondition identified at step 1104 was an interference condition or ahandoff condition. For example, if the UE 221 detects a handoffcondition at step 1104 based on a signal received from the femto node210, and determines that the UE 221 may register with the femto node210, the UE 221 may generate and transmit a request for registration atstep 1106. Some embodiments of the UE 221, however, may not beconfigured to make the determination at step 1108.

In UE 221 that are configured to make this determination, however, theUE 221 may determine that the UE 221 is not allowed to register with thefemto node and consequently does not request registration. For example,the UE 221 may use the registration module 606 to make thisdetermination. The registration module 606 may determine that the femtonode is not a preferred node of the UE 221, or may determine that thefemto node cannot be identified in a set of allowed nodes stored in thestoring module 610, for example. Techniques of determining whether a UEis allowed to register with a node were described above with respect toFIG. 6. Further, the UE 221 may determine that an interference conditionwas identified at step 1104 instead of a handoff condition.

Proceeding to step 1110, an appropriately configured UE 221 may transmitan interference communication. In some embodiments, the interferencecommunication may be transmitted directly to the femto node from whichthe signal was received at step 1102. For example, if the UE 221 isbeing served by the femto node 212 in the femto area 217 and is locatednear the femto area 215, the UE 221 may see a pilot from the femto node210 at step 1102 that has seeped out of the femto area 215. The UE 221may identify an interference condition based on the signal at step 1104,and may also determine that the UE 221 is not allowed to register withthe femto node 210. Consequently, the UE 221 may generate aninterference communication and wirelessly transmit the interferencecommunication in an OTA message, for example, to the femto node 210 atstep 1110. Transmission of an interference communication was discussedabove with respect to FIG. 6.

FIG. 12 illustrates an exemplary method 1200 of adjusting a transmissionpower for a femto node, for example the femto node 210. Although themethod 1200 will be described below with respect to elements of thefemto node 210, those of skill in the art will appreciate that othercomponents may be used to implement one or more of the steps describedherein, and that the method 1200 may be practiced by other devices.

At step 1202, a signal is transmitted, for example using thetransmitting module 502. As described above, the signal may comprise apilot signal, and may be transmitted over one or more channels. Forexample, the signal may be a pilot signal transmitted over a CPICH. Insome embodiment, the signal encodes user or voice data.

Moving to step 1204, a request for registration with the femto node 210is received, for example by the receiving module 508. The request may bewirelessly received from a UE, for example the UE 220. Requests forregistration were described above with respect to FIG. 6.

Proceeding to step 1206, it is determined that the UE requestingregistration is not allowed to register with the femto node 210, forexample using the registration unit 512. In one embodiment, therequesting UE does not belong to a CSG or a CUG of the femto node 210.For example, if the UE 220 requests registration with the femto node210, but is not identified by information stored in the registrationunit 512 and/or the storing module 504, the registration unit 512 maydetermine that the UE 220 is not allowed to register with the femto node210. Techniques for identifying UE that are allowed to register with thefemto node 210 were discussed above with respect to FIG. 5.

Next, at step 1208, a transmission power of the femto node 210 isadjusted, for example using the power adjusting module 506, based on therequest received at step 1204 or a plurality of received requests.Unsuccessful requests for registration may be an indication that thesignal transmitted at step 1202 is causing excessive interference. Forexample, the UEs requesting registration with the femto node 210 may beseeing the femto node 210 as a strong base station, and attempting todissociate with their serving nodes so that they can hand off to thefemto node 210.

In some embodiments, adjusting the power at step 1208 is event driven.For example, the power adjusting module 506 may reduce the transmissionpower be a predetermined amount or step (e.g., x dB for somepredetermined value of x) for each unsuccessful registration attemptreceived by the receiving module 508. The transmission power may begradually increased later according to a recovery schedule, for example,an increase of y dB every hour for some predetermined value of y.Further, the transmit power may be subject to lower and upper limits.The limits may be fixed, or may be adjustable based on power calibrationtechniques, for example by the power adjusting module 506.

In some embodiments, the power is only adjusted at step 1208 after apredetermined number of unsuccessful registration attempts have beenreceived. In some embodiments, the power adjusting module 506 does notadjust the transmission power unless the predetermined number ofunsuccessful registration attempts were received within a specifiedperiod of time. The power may be adjusted by an amount that isproportional to the number of unsuccessful registration attempts inexcess of the predetermined number in the specified period of time. Thepredetermined number and/or the specified time may be adjusted, forexample in conjunction with the statistical approach discussed below, ifthe power is adjusted more often than a maximum adjustment limit.

Adjusting the transmission power on an event-driven basis may increasethe response of the femto node 210 to sudden changes in the number ofUEs in the femto area 215. For example, if the femto node 215 is locatednear a bus stop, the femto node 210 can responds to a large influx ofUEs, for example when a bus full of UEs that are not allowed to registerwith the femto node 210 are nearby.

In some embodiments, adjusting the power at step 1208 is statistical.For example, the femto node 210 may determine and maintain one or morestatistics based on the unsuccessful registration attempts. In oneembodiment, the femto node 210 is configured to determine an averagenumber of unsuccessful registration attempts for a defined time period,for example a day. In another embodiment, the femto node 210 isconfigured to determine a ratio of unsuccessful registration attempts tosuccessful registration attempts. In some embodiments, the femto node210 is configured to determine a histogram of average number ofregistration attempts by hour of the day. In other embodiments, thefemto node 210 is configured to apply other statistical filters such asmoving averages or autoregressive filters on the count of unsuccessfulregistration attempts. The power for transmitting signals from thetransmitting module 502 may be adjusted based on this information, forexample according to a schedule such as at midnight every night or oncean hour.

Adjusting the transmission power using such statistics may increase theoperability of the femto node 210 in the context of recurring variationsin UE traffic. For example, the power adjusting module 506 may beconfigured to increase the transmission power at rush hour on theweekdays, or during meal times if located near a restaurant.

In some embodiments, the femto node 210 is configured to maintain arecord of UEs, for example in the storing module 504, from which itroutinely receives unsuccessful registration attempts. The femto node210 may be configured to ignore registration attempts from these UEs.For example, these UEs might belong to users that live in closeproximity to the femto node 210, or may belong to users that arevisiting the owner of the femto node 210. In some embodiments, the femtonode 210 may be configured to ignore unsuccessful registration attemptsfrom a UE if the number of unsuccessful registration attempts from thatUE exceed a maximum request limit, for example during a predeterminedtime period. In some embodiments, a user or administrator of the femtonode 210 may manually program to femto node 210 to recognize certainvisitor or neighbor UEs.

In some embodiments, the femto node 210 may receive a measurement orinformation indicative thereof that is associated with the request forregistration. For example, when a UE determines a handoff conditionbased on a signal transmitted by the femto node 210 at step 1202, the UEmay also determine a measurement to transmit to the femto node 210 withthe registration request, or may transmit information regarding thehandoff condition with the registration request. In these embodiments,adjusting the transmission power at step 1208 may be based at leastpartially on this additional received information. For example, theamount of change in the transmission power may be based on themeasurement. In some embodiments, requests for registration that areassociated with a measurement indicating an interference below athreshold are ignored by the power adjusting module 506. Those of skillin the art will appreciate other ways in which to utilize associatedmeasurement information when adjusting the power at step 1208.

As described above, the femto node 210 may adjust the transmission powerbased on a characteristic of an unsuccessful request for registration.For example, the femto node 210 may be configured to ignore a failedregistration attempt when adjusting transmission power if the failedregistration attempt is associated with a measurement indicating aninterference below a threshold. Similarly, the femto node 210 may beconfigured to consider another failed registration attempt whenadjusting transmission power if the other failed registration attempt isassociated with a measurement that is at least as great as thethreshold. In some embodiments, failed registrations attempts areweighted differently based on a characteristic. For example, failedregistration attempts received during a known rush hour, or receivedfrom a visitor UE or a UE that has exceeded a maximum request limit, mayonly count as a fraction of a failed registration attempt receivedduring a non-rush hour, or received from a non-visitor UE or UE thathasn't exceeded the maximum request limit, when the femto node 210 isdetermining or calculating an amount to adjust the transmission power.Therefore, the femto node 210 may be configured such that not all failedregistration attempts are treated equally, and the unequal treatment maybe based on characteristics of the failed registration attempts asdescribed above. Those of skill in the art will appreciate other wayscharacteristics of unsuccessful registration attempts which may beutilized by the femto node 210 for power determination.

Continuing to step 1210, a signal is transmitted, for example by thetransmitting unit 502, using the adjusted power from step 1208. Thetransmitting may comprise sending a signal similar to the signaltransmitted at step 1202, or a different type of signal than transmittedat step 1202. The signal may be wirelessly transmitted at step 1210, andmay be transmitted to any number of devices or broadcast such that itmay be received by devices in the femto area 215.

FIG. 13 illustrates an exemplary method 1300 of adjusting a transmissionpower for a femto node, for example the femto node 210. Although themethod 1300 will be described below with respect to elements of thefemto node 210, those of skill in the art will appreciate that othercomponents may be used to implement one or more of the steps describedherein, and that the method 1300 may be practiced by other devices.

At step 1302, a signal is transmitted, for example using thetransmitting module 502. As described above, the signal may comprise apilot signal, and may be transmitted over one or more channels. Forexample, the signal may be a pilot signal transmitted over a CPICH. Insome embodiment, the signal encodes user or voice data.

At step 1304, an interference communication is received, for example bythe receiving module 508. The request may be wirelessly received from aUE, for example the UE 220. Interference communications were describedabove with respect to FIG. 6.

At step 1306, a transmission power of the femto node 210 is adjusted,for example using the power adjusting module 506, based on theinterference communication received at step 1304 or a plurality ofreceived requests. Adjusting the power at step 1206 may compriseadjusting the power on an event-driven basis or on a statistical basis,for example using methods similar to those described above with respectto step 1208 of FIG. 12. Those of skill in the art will appreciate thata technique used to adjust the power at step 1306 does not need to bethe same as a technique used to adjust the power at step 1208. In someembodiments, however, the technique used at step 1306 is similar to thetechnique used at step 1208, although any thresholds or predeterminedvalues used in the techniques may vary.

In some embodiments, the femto node 210 is configured to maintain arecord of UEs, for example in the storing module 504, from which itroutinely receives interference communications. The femto node 210 maybe configured to ignore interference communications from these UEs. Insome embodiments, the femto node 210 may be configured to ignoreinterference communications from a UE if the number of suchcommunications from that UE exceed a limit, for example during apredetermined time period.

In some embodiments, the femto node 210 may receive a measurement orinformation indicative thereof that is associated with the interferencecommunication. In these embodiments, adjusting the transmission power atstep 1306 may be based at least partially on this additional receivedinformation, for example similar to the way in which adjusting the powerat step 1208 may be based on additional received information.

In some embodiments, the femto node 210 may be configured to treatrequests for registration and interference communications the same forpurposes of adjusting the power. For example, an average number ofcommunications in a specific hour of the day may be calculated from theaggregate of registration requests and interference communicationsreceived during that hour. Even if the femto node 210 does notdistinguish between registration requests and interferencecommunications for purposes of transmission power adjustment, however,the femto node 210 may be configured to handle registration requests andinterference communications separately for other functions. For example,the femto node 210 may be configured to respond to unsuccessfulregistration requests, for example with a denial message or a NACK,while being configured to send no response after receiving aninterference communication. In some embodiments, registration requestsand interference communications are handled separately by the femto node210 for purposes of transmission power adjustment, for example bydifferent state machines of the femto node 210. Thus, a statistic forregistration requests may be maintained separate from a statistic forinterference communications.

Moving to step 1308, a signal is transmitted, for example by thetransmitting unit 502, using the adjusted power from step 1206. Thetransmitting may comprise sending a signal similar to the signaltransmitted at step 1302, or a different type of signal than transmittedat step 1302. The signal may be wirelessly transmitted at step 1308, andmay be transmitted to any number of devices or broadcast such that itmay be received by devices in the femto area 215.

Those of skill in the art will appreciate that the devices, systems, andmethods described herein may be used to adjust the power of a femtonode. For example, femto nodes or other are low power basestations maybe deployed along with conventional WAN basestations such MNBs in awireless network. The femot nodes may be configured to provide superiordata rates and coverage to home subscribers. These femto nodes, however,may be deployed in an unplanned fashion. Thus, management ofinterference caused by the femto nodes to the macro network or nearbyfemto nodes is advantageous. Those of skill in the art will appreciatethat the devices, systems, and methods described herein may be used toprotect MUEs or other UEs not communicating with a femto node (forexample UEs that are not in the CSG of the femto node) from interferenceby adjusting or limiting the transmit power of the femto node, forexample for pilot, overhead and data channels. These devices, systems,and methods may strike a balance between the femto coverage area andinterference impact on MUEs In this way, inaccurate power settings forthe femto node, for example due to assumptions made by the networklisten module, may be reduced or avoided. For example, situations wheretoo much interference for MUEs can be reduced, as can situations ofinadequate coverage for the femto node. In addition, femto nodes asdescribed herein may be traffic aware, for example considering whetherany MUEs are actually being affected by the power setting of the femtonode. Those of skill in the art will appreciate that the devices,systems, and methods described herein may be used in conjunction withpower adjustment schemes known in the art, for example methods relyingon measurements from the network listen module.

As described above, the devices, systems, and methods described hereinmay be used to adjust the power of a femto node. Using these devices,systems, and methods, femto nodes may consider whether they are causingor not causing interference to MUEs or if there are even any MUEspresent. Furthermore, the femto nodes may consider situations where amismatch exists between the RF conditions seen by a network listenmodule and a UE. Further, transmission power may be adjusted fordeployments where initial parameters configured for self calibration arenot valid. In these situations, the devices, systems, and methodsdescribed herein may achieve the desired coverage for HUEs while keepingthe interference to other users (macro or neighbor femto) low. Femtonodes described herein may be made aware of true traffic conditions ofMUEs in the femto node vicinity. If there are no or few MUEs beingaffected by transmissions of the femto node, the femto area may beincreased. If a significant number of MUEs are being interfered with,the femto node may be able to appropriately respond. In someembodiments, messaging from the macro network is not required, as thefemto node may receive communications directly from UEs or other femtonodes. Some embodiments describe techniques that may account for asudden influx of MUEs. In addition, statistics-based techniques may beused to respond to time variations in MUE traffic. Further, techniquesdescribed herein may provide backoff mechanisms which allow aggressiveinitial setting of the femto node transmission power with appropriatesubsequent reduction of the transmit power, for example which may bebeneficial for large houses or other large femto areas.

Although described separately, it is to be appreciated that functionalblocks described with respect to FIGS. 4, 5, 6, and 7 need not beseparate structural elements. For example, the power adjusting module506 and the registration unit 512 may be embodied in a single chip. Somemodules may be implemented by a processing module, either separately orjointly. The processing module may contain memory, such as registers.Similarly, one or more of the functional blocks or portions of thefunctionality of various blocks may be embodied in a single chip.Alternatively, the functionality of a particular block may beimplemented on two or more chips.

One or more of the functional blocks and/or one or more combinations ofthe functional blocks described with respect to FIGS. 4, 5, 6, and 7,such as the processing power adjusting module 506, signal measuringmodule 64, and/or the statistic module 704, may be embodied as a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, or any suitable combination thereofdesigned to perform the functions described herein. One or more of thefunctional blocks and/or one or more combinations of the functionalblocks described with respect to FIGS. 4, 5, 6, and 7 may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP communication, or anyother such configuration.

The functionality described herein (e.g., with regard to one or more ofthe accompanying figures) may correspond in some aspects to similarlydesignated “means for” functionality in the appended claims. Referringto FIGS. 5, 6, and 7, the femto node 210, the UE 222, and the macro node205 are represented as a series of interrelated functional modules.

The functionality of the modules of FIGS. 4, 5, 6, and 7 may beimplemented in various ways consistent with the teachings herein. Insome aspects the functionality of these modules may be implemented asone or more electrical components. In some aspects the functionality ofthese blocks may be implemented as a processing system including one ormore processor components. In some aspects the functionality of thesemodules may be implemented using, for example, at least a portion of oneor more integrated circuits (e.g., an ASIC). As discussed herein, anintegrated circuit may include a processor, software, other relatedcomponents, or some combination thereof The functionality of thesemodules also may be implemented in some other manner as taught herein.

It should be understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations may be used herein as a convenient method of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements may be employed there or that the first element must precedethe second element in some manner. Also, unless stated otherwise a setof elements may comprise one or more elements. In addition, terminologyof the form “at least one of: A, B, or C” used in the description or theclaims means “A or B or C or any combination of these elements.”

While the specification describes particular examples of the presentinvention, those of ordinary skill can devise variations of the presentinvention without departing from the inventive concept. For example,some of the teachings herein may refer to circuit-switched networkelements but are equally applicable to packet-switched domain networkelements.

Those skilled in the art will understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those skilled in the art will further appreciate that the variousillustrative logical blocks, modules, circuits, methods and algorithmsdescribed in connection with the examples disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,methods and algorithms have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentinvention.

The methods or algorithms described in connection with the examplesdisclosed herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. A storagemedium may be coupled to the processor such that the processor can readinformation from, and write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Theprocessor and the storage medium may reside in an ASIC.

In one or more exemplary embodiments, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosed examples is provided to enableany person skilled in the art to make or use the present invention.Various modifications to these examples will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other examples without departing from the spirit or scopeof the invention. Thus, the present invention is not intended to belimited to the examples shown herein but is to be accorded the widestscope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. An apparatus for wireless communication, theapparatus comprising: a receiver configured to wirelessly receive asignal transmitted from a transmitting device, the transmitting devicebeing associated with at least one user device, wherein only userdevices that are associated with the transmitting device are permittedto communicate with other user devices via the transmitting device; aninterference unit configured to identify an interference condition basedat least in part on the received signal; a determination unit configuredto determine whether the apparatus is associated with the transmittingdevice; and a transmitter configured to wirelessly transmit aninterference communication to the transmitting device in response toidentifying the interference condition if the apparatus is notassociated with the transmitting device.
 2. The apparatus of claim 1,wherein the interference condition is identified when path loss of thesignal is greater than a predetermined threshold.
 3. The apparatus ofclaim 1, wherein the transmitter is configured to transmit informationindicative of a measurement to the transmitting device, the measurementbeing based at least in part on the received signal.
 4. The apparatus ofclaim 3, wherein the measurement comprises an Ec/Io measurement of thereceived signal.
 5. The apparatus of claim 3, wherein the measurementcomprises a received signal code power (RSCP) of the received signal. 6.The apparatus of claim 1, wherein the transmitter is configured towirelessly transmit the interference communication in an over-the-air(OTA) message addressed to the transmitting device.
 7. The apparatus ofclaim 1, wherein the transmitter is configured to wirelessly transmitthe interference communication using a random access channel (RACH)procedure.
 8. The apparatus of claim 1, wherein the transmitting devicecomprises a femto node.
 9. A method of wireless communication, themethod comprising: wirelessly receiving at an apparatus a signaltransmitted from a transmitting device, the transmitting device beingassociated with at least one user device, wherein only user devices thatare associated with the transmitting device are permitted to communicatewith other user devices via the transmitting device; identifying aninterference condition based at least in part on the received signal;determining whether the apparatus is associated with the transmittingdevice; and wirelessly transmitting an interference communication to thetransmitting device in response to identifying the interferencecondition if the apparatus is not associated with the transmittingdevice.
 10. The method of claim 9, wherein the interference condition isidentified when path loss of the signal is greater than a predeterminedthreshold.
 11. The method of claim 9, wherein the identifying comprisesdetermining a measurement based at least in part on the received signal,and wherein the method further comprises transmitting informationindicative of the measurement to the transmitting device.
 12. The methodof claim 11, wherein the measurement comprises an Ec/Io measurement ofthe received signal.
 13. The method of claim 11, wherein the measurementcomprises a received signal code power (RSCP) of the received signal.14. The method of claim 9, wherein the transmitting comprises wirelesslytransmitting the interference communication in an over-the-air (OTA)message addressed to the transmitting device.
 15. The method of claim 9,wherein the transmitting comprises wirelessly transmitting theinterference communication using a random access channel (RACH)procedure.
 16. The method of claim 9, wherein the transmitting devicecomprises a femto node.
 17. An apparatus for wireless communication, theapparatus comprising: means for wirelessly receiving at an apparatus asignal transmitted from a transmitting device, the transmitting devicebeing associated with at least one user device, wherein only userdevices that are associated with the transmitting device are permittedto communicate with other user devices via the transmitting device;means for identifying an interference condition based at least in parton the received signal; means for determining whether the apparatus isassociated with the transmitting device; and means for wirelesslytransmitting an interference communication to the transmitting device inresponse to identifying the interference condition if the apparatus isnot associated with the transmitting device.
 18. The apparatus of claim17, wherein the interference condition is identified when path loss ofthe signal is greater than a predetermined threshold.
 19. The apparatusof claim 17, wherein the identifying means comprises means fordetermining a measurement based at least in part on the received signal,and wherein the apparatus further comprises means for transmittinginformation indicative of the measurement to the transmitting device.20. The apparatus of claim 19, wherein the measurement comprises anEc/Io measurement of the received signal.
 21. The apparatus of claim 19,wherein the measurement comprises a received signal code power (RSCP) ofthe received signal.
 22. The apparatus of claim 17, wherein thetransmitting means comprises means for wirelessly transmitting theinterference communication in an over-the-air (OTA) message addressed tothe transmitting device.
 23. The apparatus of claim 17, wherein thetransmitting means comprises means for wirelessly transmitting theinterference communication using a random access channel (RACH)procedure.
 24. The apparatus of claim 17, wherein the transmittingdevice comprises a femto node.
 25. A non-transitory computer-readablemedium comprising: code for causing a computer to wirelessly receive asignal transmitted from a transmitting device, the transmitting devicebeing associated with at least one user device, wherein only userdevices that are associated with the transmitting device are permittedto communicate with other user devices via the transmitting device; codefor causing the computer to identify an interference condition based atleast in part on the received signal; code for causing the computer todetermine whether a device of the computer which received the signal isassociated with the transmitting device; and code for causing thecomputer to wirelessly transmitting an interference communication to thetransmitting device in response to identifying the interferencecondition if the device of the computer is not associated with thetransmitting device.
 26. The non-transitory computer-readable medium ofclaim 25, wherein the interference condition is identified when pathloss of the signal is greater than a predetermined threshold.
 27. Thenon-transitory computer-readable medium of claim 25, wherein the codefor causing the computer to identify comprises code for causing thecomputer to determine a measurement based at least in part on thereceived signal, and wherein the computer-readable medium furthercomprises code for causing the computer to transmit informationindicative of the measurement to the transmitting device.
 28. Thenon-transitory computer-readable medium of claim 27, wherein themeasurement comprises an Ec/Io measurement of the received signal. 29.The non-transitory computer-readable medium of claim 27, wherein themeasurement comprises a received signal code power (RSCP) of thereceived signal.
 30. The non-transitory computer-readable medium ofclaim 25, wherein the code for causing the computer to wirelesslytransmit comprises code for causing the computer to wirelessly transmitthe interference communication in an over-the-air (OTA) messageaddressed to the transmitting device.
 31. The non-transitorycomputer-readable medium of claim 25, wherein the code for causing thecomputer to wirelessly transmit comprises code for causing the computerto wirelessly transmit the interference communication using a randomaccess channel (RACH) procedure.
 32. The non-transitorycomputer-readable medium of claim 25, wherein the transmitting devicecomprises a femto node.